diff --git a/frontend/src/__tests__/app/message-plans/choose-email-template/preview-template/__snapshots__/page.test.tsx.snap b/frontend/src/__tests__/app/message-plans/choose-email-template/preview-template/__snapshots__/page.test.tsx.snap
index 0500bddc5..28374218f 100644
--- a/frontend/src/__tests__/app/message-plans/choose-email-template/preview-template/__snapshots__/page.test.tsx.snap
+++ b/frontend/src/__tests__/app/message-plans/choose-email-template/preview-template/__snapshots__/page.test.tsx.snap
@@ -32,7 +32,6 @@ exports[`PreviewEmailTemplateFromMessagePlan page renders Email template preview
               Template
             </span>
             <h1
-              class="preview__heading"
               data-testid="preview-message__heading"
             >
               email template name
diff --git a/frontend/src/__tests__/app/message-plans/choose-large-print-letter-template/preview-template/__snapshots__/page.test.tsx.snap b/frontend/src/__tests__/app/message-plans/choose-large-print-letter-template/preview-template/__snapshots__/page.test.tsx.snap
index bae492c24..f2746d037 100644
--- a/frontend/src/__tests__/app/message-plans/choose-large-print-letter-template/preview-template/__snapshots__/page.test.tsx.snap
+++ b/frontend/src/__tests__/app/message-plans/choose-large-print-letter-template/preview-template/__snapshots__/page.test.tsx.snap
@@ -32,7 +32,6 @@ exports[`PreviewLargePrintLetterTemplateFromMessagePlan page renders large print
               Template
             </span>
             <h1
-              class="preview__heading"
               data-testid="preview-message__heading"
             >
               large print letter template name
diff --git a/frontend/src/__tests__/app/message-plans/choose-nhs-app-template/preview-template/__snapshots__/page.test.tsx.snap b/frontend/src/__tests__/app/message-plans/choose-nhs-app-template/preview-template/__snapshots__/page.test.tsx.snap
index adc53a293..4bebefd8a 100644
--- a/frontend/src/__tests__/app/message-plans/choose-nhs-app-template/preview-template/__snapshots__/page.test.tsx.snap
+++ b/frontend/src/__tests__/app/message-plans/choose-nhs-app-template/preview-template/__snapshots__/page.test.tsx.snap
@@ -32,7 +32,6 @@ exports[`PreviewNhsAppTemplateFromMessagePlan page renders NHS App template prev
               Template
             </span>
             <h1
-              class="preview__heading"
               data-testid="preview-message__heading"
             >
               app template name
diff --git a/frontend/src/__tests__/app/message-plans/choose-other-language-letter-template/[routingConfigId]/preview-template/[templateId]/__snapshots__/page.test.tsx.snap b/frontend/src/__tests__/app/message-plans/choose-other-language-letter-template/[routingConfigId]/preview-template/[templateId]/__snapshots__/page.test.tsx.snap
index eb9ef4fe4..2ca062b54 100644
--- a/frontend/src/__tests__/app/message-plans/choose-other-language-letter-template/[routingConfigId]/preview-template/[templateId]/__snapshots__/page.test.tsx.snap
+++ b/frontend/src/__tests__/app/message-plans/choose-other-language-letter-template/[routingConfigId]/preview-template/[templateId]/__snapshots__/page.test.tsx.snap
@@ -32,7 +32,6 @@ exports[`PreviewOtherLanguageLetterTemplateFromMessagePlan page renders foreign
               Template
             </span>
             <h1
-              class="preview__heading"
               data-testid="preview-message__heading"
             >
               French letter template
diff --git a/frontend/src/__tests__/app/message-plans/choose-standard-english-letter-template/preview-template/__snapshots__/page.test.tsx.snap b/frontend/src/__tests__/app/message-plans/choose-standard-english-letter-template/preview-template/__snapshots__/page.test.tsx.snap
index eb9af4a2c..d5b6d634d 100644
--- a/frontend/src/__tests__/app/message-plans/choose-standard-english-letter-template/preview-template/__snapshots__/page.test.tsx.snap
+++ b/frontend/src/__tests__/app/message-plans/choose-standard-english-letter-template/preview-template/__snapshots__/page.test.tsx.snap
@@ -32,7 +32,6 @@ exports[`PreviewStandardEnglishLetterTemplateFromMessagePlan page renders letter
               Template
             </span>
             <h1
-              class="preview__heading"
               data-testid="preview-message__heading"
             >
               letter template name
diff --git a/frontend/src/__tests__/app/message-plans/choose-text-message-template/preview-template/__snapshots__/page.test.tsx.snap b/frontend/src/__tests__/app/message-plans/choose-text-message-template/preview-template/__snapshots__/page.test.tsx.snap
index a484478a6..1b901e9c9 100644
--- a/frontend/src/__tests__/app/message-plans/choose-text-message-template/preview-template/__snapshots__/page.test.tsx.snap
+++ b/frontend/src/__tests__/app/message-plans/choose-text-message-template/preview-template/__snapshots__/page.test.tsx.snap
@@ -32,7 +32,6 @@ exports[`PreviewTextMessageTemplateFromMessagePlan page renders SMS template pre
               Template
             </span>
             <h1
-              class="preview__heading"
               data-testid="preview-message__heading"
             >
               sms template name
diff --git a/frontend/src/__tests__/app/preview-letter-template/__snapshots__/page.test.tsx.snap b/frontend/src/__tests__/app/preview-letter-template/__snapshots__/page.test.tsx.snap
index af755cecd..9d1f6dbf5 100644
--- a/frontend/src/__tests__/app/preview-letter-template/__snapshots__/page.test.tsx.snap
+++ b/frontend/src/__tests__/app/preview-letter-template/__snapshots__/page.test.tsx.snap
@@ -71,7 +71,6 @@ exports[`authoring letter template with VALIDATION_FAILED status matches snapsho
                 Template
               </span>
               <h1
-                class="preview__heading"
                 data-testid="preview-message__heading"
               >
                 authoring letter template name
@@ -222,6 +221,8 @@ exports[`authoring letter template with VALIDATION_FAILED status matches snapsho
         <a
           class="nhsuk-body"
           href="https://notify.nhs.uk/using-nhs-notify/personalisation"
+          rel="noopener noreferrer"
+          target="_blank"
         >
           Learn more about personalising your letters (opens in a new tab).
         </a>
@@ -627,7 +628,6 @@ exports[`authoring letter template with VALIDATION_FAILED status matches snapsho
                 Template
               </span>
               <h1
-                class="preview__heading"
                 data-testid="preview-message__heading"
               >
                 authoring letter template name
@@ -778,6 +778,8 @@ exports[`authoring letter template with VALIDATION_FAILED status matches snapsho
         <a
           class="nhsuk-body"
           href="https://notify.nhs.uk/using-nhs-notify/personalisation"
+          rel="noopener noreferrer"
+          target="_blank"
         >
           Learn more about personalising your letters (opens in a new tab).
         </a>
@@ -1176,7 +1178,6 @@ exports[`valid PDF letter template matches snapshot 1`] = `
               Template
             </span>
             <h1
-              class="preview__heading"
               data-testid="preview-message__heading"
             >
               letter template name
@@ -1339,7 +1340,6 @@ exports[`valid authoring letter template matches snapshot 1`] = `
                 Template
               </span>
               <h1
-                class="preview__heading"
                 data-testid="preview-message__heading"
               >
                 authoring letter template name
@@ -1563,6 +1563,8 @@ exports[`valid authoring letter template matches snapshot 1`] = `
         <a
           class="nhsuk-body"
           href="https://notify.nhs.uk/using-nhs-notify/personalisation"
+          rel="noopener noreferrer"
+          target="_blank"
         >
           Learn more about personalising your letters (opens in a new tab).
         </a>
diff --git a/frontend/src/__tests__/app/preview-letter-template/server-action.test.ts b/frontend/src/__tests__/app/preview-letter-template/server-action.test.ts
index 9fb1999a7..eb5c17dfc 100644
--- a/frontend/src/__tests__/app/preview-letter-template/server-action.test.ts
+++ b/frontend/src/__tests__/app/preview-letter-template/server-action.test.ts
@@ -21,7 +21,7 @@ describe('submitAuthoringLetterAction', () => {
     await submitAuthoringLetterAction({}, formData);
 
     expect(redirectMock).toHaveBeenCalledWith(
-      '/submit-letter-template/template-123?lockNumber=1'
+      '/review-and-approve-letter-template/template-123?lockNumber=1'
     );
   });
 
diff --git a/frontend/src/__tests__/app/review-and-approve-letter-template/__snapshots__/page.test.tsx.snap b/frontend/src/__tests__/app/review-and-approve-letter-template/__snapshots__/page.test.tsx.snap
new file mode 100644
index 000000000..8d1b454d9
--- /dev/null
+++ b/frontend/src/__tests__/app/review-and-approve-letter-template/__snapshots__/page.test.tsx.snap
@@ -0,0 +1,238 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`valid authoring letter template matches snapshot 1`] = `
+<DocumentFragment>
+  <div
+    class="nhsuk-width-container"
+  >
+    <main
+      class="nhsuk-main-wrapper"
+      id="maincontent"
+      role="main"
+    >
+      <div
+        class="nhsuk-u-reading-width"
+      >
+        <span
+          class="nhsuk-caption-l"
+        >
+          Step 2 of 2
+        </span>
+        <h1
+          data-testid="preview-message__heading"
+        >
+          Review and approve 'authoring letter template name'
+        </h1>
+      </div>
+      <div
+        class="nhsuk-width-container nhsuk-u-margin-bottom-6 nhsuk-body-m"
+      >
+        <dl
+          class="nhsuk-summary-list nhsuk-u-margin-bottom-4 preview authoringLetterDetails"
+        >
+          <div
+            class="nhsuk-summary-list__row"
+          >
+            <dt
+              class="nhsuk-summary-list__key"
+            >
+              Template ID
+            </dt>
+            <dd
+              class="nhsuk-summary-list__value monospace-font"
+              data-testid="preview-template-id"
+            >
+              authoring-letter-template-id
+            </dd>
+            <dd
+              class="nhsuk-summary-list__actions"
+            />
+          </div>
+          <div
+            class="nhsuk-summary-list__row"
+          >
+            <dt
+              class="nhsuk-summary-list__key"
+            >
+              Template type
+            </dt>
+            <dd
+              class="nhsuk-summary-list__value"
+            >
+              Standard letter
+            </dd>
+            <dd
+              class="nhsuk-summary-list__actions"
+            />
+          </div>
+          <div
+            class="nhsuk-summary-list__row missing-value"
+            id="campaign-id"
+          >
+            <dt
+              class="nhsuk-summary-list__key"
+            >
+              Campaign
+            </dt>
+            <dd
+              class="nhsuk-summary-list__value"
+            />
+            <dd
+              aria-hidden="true"
+              class="nhsuk-summary-list__actions"
+            />
+          </div>
+          <div
+            class="nhsuk-summary-list__row"
+          >
+            <dt
+              class="nhsuk-summary-list__key"
+            >
+              Total pages
+            </dt>
+            <dd
+              class="nhsuk-summary-list__value"
+            >
+              2
+            </dd>
+            <dd
+              class="nhsuk-summary-list__actions"
+            />
+          </div>
+          <div
+            class="nhsuk-summary-list__row"
+          >
+            <dt
+              class="nhsuk-summary-list__key"
+            >
+              Sheets
+            </dt>
+            <dd
+              class="nhsuk-summary-list__value"
+            >
+              1
+            </dd>
+            <dd
+              aria-hidden="true"
+              class="nhsuk-summary-list__actions"
+            />
+          </div>
+          <div
+            class="nhsuk-summary-list__row"
+            id="printing-and-postage"
+          >
+            <dt
+              class="nhsuk-summary-list__key"
+            >
+              Printing and postage
+            </dt>
+            <dd
+              class="nhsuk-summary-list__value"
+            >
+              Standard C5
+            </dd>
+            <dd
+              aria-hidden="true"
+              class="nhsuk-summary-list__actions"
+            />
+          </div>
+          <div
+            class="nhsuk-summary-list__row"
+          >
+            <dt
+              class="nhsuk-summary-list__key"
+            >
+              Status
+            </dt>
+            <dd
+              class="nhsuk-summary-list__value"
+            >
+              <strong
+                class="nhsuk-tag nhsuk-tag--yellow"
+                data-status="not-yet-submitted"
+                data-testid="status-tag"
+              >
+                Approval needed
+              </strong>
+            </dd>
+            <dd
+              aria-hidden="true"
+              class="nhsuk-summary-list__actions"
+            />
+          </div>
+        </dl>
+      </div>
+      <h2
+        class="nhsuk-heading-m"
+      >
+        Short example preview
+      </h2>
+      <iframe
+        aria-label="PDF preview of letter template with short example personalisation data"
+        class="iframe nhsuk-u-margin-bottom-6"
+        src="/templates/files/client-123/renders/authoring-letter-template-id/short-form.pdf"
+        title="Letter preview - short examples"
+      />
+      <h2
+        class="nhsuk-heading-m"
+      >
+        Long example preview
+      </h2>
+      <iframe
+        aria-label="PDF preview of letter template with long example personalisation data"
+        class="iframe nhsuk-u-margin-bottom-6"
+        src="/templates/files/client-123/renders/authoring-letter-template-id/long-form.pdf"
+        title="Letter preview - long examples"
+      />
+      <form
+        action="javascript:throw new Error('A React form was unexpectedly submitted. If you called form.submit() manually, consider using form.requestSubmit() instead. If you\\'re trying to use event.stopPropagation() in a submit event handler, consider also calling event.preventDefault().')"
+      >
+        <input
+          name="form-id"
+          readonly=""
+          type="hidden"
+          value="review-and-approve-letter"
+        />
+        <input
+          name="csrf_token"
+          readonly=""
+          type="hidden"
+          value="no_token"
+        />
+        <input
+          name="templateId"
+          type="hidden"
+          value="authoring-letter-template-id"
+        />
+        <input
+          name="lockNumber"
+          type="hidden"
+          value="1"
+        />
+        <div
+          class="nhsuk-form-group"
+        >
+          <button
+            aria-disabled="false"
+            class="nhsuk-button"
+            type="submit"
+          >
+            Approve letter template
+          </button>
+          <a
+            aria-disabled="false"
+            class="nhsuk-button nhsuk-button--secondary nhsuk-u-margin-left-3"
+            data-testid="back-link-bottom"
+            draggable="false"
+            href="/templates/get-ready-to-approve-letter-template/authoring-letter-template-id"
+            id="go-back-button"
+            role="button"
+          >
+            Go back
+          </a>
+        </div>
+      </form>
+    </main>
+  </div>
+</DocumentFragment>
+`;
diff --git a/frontend/src/__tests__/app/review-and-approve-letter-template/page.test.tsx b/frontend/src/__tests__/app/review-and-approve-letter-template/page.test.tsx
new file mode 100644
index 000000000..e2bff4c00
--- /dev/null
+++ b/frontend/src/__tests__/app/review-and-approve-letter-template/page.test.tsx
@@ -0,0 +1,385 @@
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { redirect, RedirectType } from 'next/navigation';
+import { getLetterVariantById, getTemplate } from '@utils/form-actions';
+import { verifyFormCsrfToken } from '@utils/csrf-utils';
+import {
+  AUTHORING_LETTER_TEMPLATE,
+  EMAIL_TEMPLATE,
+  NHS_APP_TEMPLATE,
+  PDF_LETTER_TEMPLATE,
+  SMS_TEMPLATE,
+  makeLetterVariant,
+} from '@testhelpers/helpers';
+import { AuthoringLetterTemplate } from 'nhs-notify-web-template-management-utils';
+import Page, {
+  generateMetadata,
+} from '@app/review-and-approve-letter-template/[templateId]/page';
+import { reviewAndApproveLetterTemplateAction } from '@app/review-and-approve-letter-template/[templateId]/server-action';
+
+jest.mock('@utils/form-actions');
+jest.mock('next/navigation');
+jest.mock('@app/review-and-approve-letter-template/[templateId]/server-action');
+jest.mock('@utils/csrf-utils');
+
+const templateWithRenderedFiles: AuthoringLetterTemplate = {
+  ...AUTHORING_LETTER_TEMPLATE,
+  clientId: 'client-123',
+  files: {
+    ...AUTHORING_LETTER_TEMPLATE.files,
+    shortFormRender: {
+      fileName: 'short-form.pdf',
+      currentVersion: 'v1',
+      status: 'RENDERED',
+      pageCount: 1,
+    },
+    longFormRender: {
+      fileName: 'long-form.pdf',
+      currentVersion: 'v2',
+      status: 'RENDERED',
+      pageCount: 3,
+    },
+  },
+};
+
+const defaultSearchParams = Promise.resolve({
+  lockNumber: String(templateWithRenderedFiles.lockNumber),
+});
+
+beforeEach(() => {
+  jest.resetAllMocks();
+  jest.mocked(reviewAndApproveLetterTemplateAction).mockResolvedValue({});
+  jest.mocked(verifyFormCsrfToken).mockResolvedValue(true);
+  jest.mocked(getLetterVariantById).mockResolvedValue(makeLetterVariant());
+});
+
+test('metadata', async () => {
+  expect(await generateMetadata()).toEqual({
+    title: 'Review and approve letter template - NHS Notify',
+  });
+});
+
+describe('template does not exist', () => {
+  beforeEach(() => {
+    jest.mocked(getTemplate).mockResolvedValue(undefined);
+  });
+
+  it('redirects to invalid template page', async () => {
+    await Page({
+      params: Promise.resolve({ templateId: 'template-123' }),
+      searchParams: defaultSearchParams,
+    });
+
+    expect(redirect).toHaveBeenCalledWith(
+      '/invalid-template',
+      RedirectType.replace
+    );
+  });
+});
+
+describe('template is not a letter', () => {
+  it('redirects to invalid template page when template is an email', async () => {
+    jest.mocked(getTemplate).mockResolvedValue(EMAIL_TEMPLATE);
+
+    await Page({
+      params: Promise.resolve({ templateId: EMAIL_TEMPLATE.id }),
+      searchParams: defaultSearchParams,
+    });
+
+    expect(redirect).toHaveBeenCalledWith(
+      '/invalid-template',
+      RedirectType.replace
+    );
+  });
+
+  it('redirects to invalid template page when template is an SMS', async () => {
+    jest.mocked(getTemplate).mockResolvedValue(SMS_TEMPLATE);
+
+    await Page({
+      params: Promise.resolve({ templateId: SMS_TEMPLATE.id }),
+      searchParams: defaultSearchParams,
+    });
+
+    expect(redirect).toHaveBeenCalledWith(
+      '/invalid-template',
+      RedirectType.replace
+    );
+  });
+
+  it('redirects to invalid template page when template is an NHS App message', async () => {
+    jest.mocked(getTemplate).mockResolvedValue(NHS_APP_TEMPLATE);
+
+    await Page({
+      params: Promise.resolve({ templateId: NHS_APP_TEMPLATE.id }),
+      searchParams: defaultSearchParams,
+    });
+
+    expect(redirect).toHaveBeenCalledWith(
+      '/invalid-template',
+      RedirectType.replace
+    );
+  });
+});
+
+describe('template is a PDF letter (not AUTHORING)', () => {
+  it('redirects to invalid template page when letterVersion is PDF', async () => {
+    jest.mocked(getTemplate).mockResolvedValue(PDF_LETTER_TEMPLATE);
+
+    await Page({
+      params: Promise.resolve({ templateId: PDF_LETTER_TEMPLATE.id }),
+      searchParams: defaultSearchParams,
+    });
+
+    expect(redirect).toHaveBeenCalledWith(
+      '/invalid-template',
+      RedirectType.replace
+    );
+  });
+});
+
+describe('lockNumber validation', () => {
+  beforeEach(() => {
+    jest.mocked(getTemplate).mockResolvedValue(templateWithRenderedFiles);
+  });
+
+  it('redirects to preview page when lockNumber is missing from searchParams', async () => {
+    await Page({
+      params: Promise.resolve({
+        templateId: templateWithRenderedFiles.id,
+      }),
+      searchParams: Promise.resolve({}),
+    });
+
+    expect(redirect).toHaveBeenCalledWith(
+      `/preview-letter-template/${templateWithRenderedFiles.id}`,
+      RedirectType.replace
+    );
+  });
+
+  it('redirects to preview page when lockNumber does not match template', async () => {
+    await Page({
+      params: Promise.resolve({
+        templateId: templateWithRenderedFiles.id,
+      }),
+      searchParams: Promise.resolve({ lockNumber: '999' }),
+    });
+
+    expect(redirect).toHaveBeenCalledWith(
+      `/preview-letter-template/${templateWithRenderedFiles.id}`,
+      RedirectType.replace
+    );
+  });
+
+  it('redirects to preview page when lockNumber is not a valid number', async () => {
+    await Page({
+      params: Promise.resolve({
+        templateId: templateWithRenderedFiles.id,
+      }),
+      searchParams: Promise.resolve({ lockNumber: 'abc' }),
+    });
+
+    expect(redirect).toHaveBeenCalledWith(
+      `/preview-letter-template/${templateWithRenderedFiles.id}`,
+      RedirectType.replace
+    );
+  });
+
+  it('redirects to preview page when template has no letterVariantId', async () => {
+    const templateWithoutVariant: AuthoringLetterTemplate = {
+      ...templateWithRenderedFiles,
+      letterVariantId: undefined,
+    };
+
+    jest.mocked(getTemplate).mockResolvedValue(templateWithoutVariant);
+
+    await Page({
+      params: Promise.resolve({
+        templateId: templateWithoutVariant.id,
+      }),
+      searchParams: Promise.resolve({
+        lockNumber: String(templateWithoutVariant.lockNumber),
+      }),
+    });
+
+    expect(redirect).toHaveBeenCalledWith(
+      `/preview-letter-template/${templateWithoutVariant.id}`,
+      RedirectType.replace
+    );
+  });
+
+  it('redirects to preview page when template is missing an expected render', async () => {
+    const templateNoLongFormRender: AuthoringLetterTemplate = {
+      ...templateWithRenderedFiles,
+      files: { ...templateWithRenderedFiles.files, longFormRender: undefined },
+    };
+
+    jest.mocked(getTemplate).mockResolvedValue(templateNoLongFormRender);
+
+    await Page({
+      params: Promise.resolve({
+        templateId: templateNoLongFormRender.id,
+      }),
+      searchParams: Promise.resolve({
+        lockNumber: String(templateNoLongFormRender.lockNumber),
+      }),
+    });
+
+    expect(redirect).toHaveBeenCalledWith(
+      `/preview-letter-template/${templateNoLongFormRender.id}`,
+      RedirectType.replace
+    );
+  });
+
+  it('redirects to preview page when a render is not in expected RENDERED status', async () => {
+    const templatePendingRender: AuthoringLetterTemplate = {
+      ...templateWithRenderedFiles,
+      files: {
+        ...templateWithRenderedFiles.files,
+        shortFormRender: {
+          status: 'PENDING',
+          requestedAt: '2026-03-18T08:08:04.547Z',
+        },
+      },
+    };
+
+    jest.mocked(getTemplate).mockResolvedValue(templatePendingRender);
+
+    await Page({
+      params: Promise.resolve({
+        templateId: templatePendingRender.id,
+      }),
+      searchParams: Promise.resolve({
+        lockNumber: String(templatePendingRender.lockNumber),
+      }),
+    });
+
+    expect(redirect).toHaveBeenCalledWith(
+      `/preview-letter-template/${templatePendingRender.id}`,
+      RedirectType.replace
+    );
+  });
+});
+
+describe('valid authoring letter template', () => {
+  beforeEach(() => {
+    jest.mocked(getTemplate).mockResolvedValue(templateWithRenderedFiles);
+  });
+
+  it('renders the page without redirecting', async () => {
+    const page = await Page({
+      params: Promise.resolve({ templateId: templateWithRenderedFiles.id }),
+      searchParams: defaultSearchParams,
+    });
+
+    expect(page).toBeTruthy();
+    expect(redirect).not.toHaveBeenCalled();
+  });
+
+  it('calls getLetterVariantById with the template letterVariantId', async () => {
+    await Page({
+      params: Promise.resolve({ templateId: templateWithRenderedFiles.id }),
+      searchParams: defaultSearchParams,
+    });
+
+    expect(getLetterVariantById).toHaveBeenCalledWith(
+      templateWithRenderedFiles.letterVariantId
+    );
+  });
+
+  it('renders the heading and caption', async () => {
+    render(
+      await Page({
+        params: Promise.resolve({ templateId: templateWithRenderedFiles.id }),
+        searchParams: defaultSearchParams,
+      })
+    );
+
+    expect(screen.getByTestId('preview-message__heading')).toHaveTextContent(
+      `Review and approve 'authoring letter template name'`
+    );
+    expect(screen.getByText('Step 2 of 2')).toBeInTheDocument();
+  });
+
+  it('renders hidden templateId and lockNumber inputs', async () => {
+    render(
+      await Page({
+        params: Promise.resolve({ templateId: templateWithRenderedFiles.id }),
+        searchParams: defaultSearchParams,
+      })
+    );
+
+    const form = screen.getByRole('button', {
+      name: 'Approve letter template',
+    });
+    expect(form).toBeInTheDocument();
+  });
+
+  it('submits the form with correct data', async () => {
+    const user = userEvent.setup();
+
+    render(
+      await Page({
+        params: Promise.resolve({ templateId: templateWithRenderedFiles.id }),
+        searchParams: defaultSearchParams,
+      })
+    );
+
+    await user.click(
+      screen.getByRole('button', { name: 'Approve letter template' })
+    );
+
+    expect(reviewAndApproveLetterTemplateAction).toHaveBeenCalledTimes(1);
+
+    const formData = jest.mocked(reviewAndApproveLetterTemplateAction).mock
+      .calls[0][1] as FormData;
+
+    expect(formData.get('templateId')).toBe(templateWithRenderedFiles.id);
+
+    expect(formData.get('lockNumber')).toBe(
+      String(templateWithRenderedFiles.lockNumber)
+    );
+  });
+
+  it('renders iframes with PDF URLs when renders are available', async () => {
+    render(
+      await Page({
+        params: Promise.resolve({
+          templateId: templateWithRenderedFiles.id,
+        }),
+        searchParams: Promise.resolve({
+          lockNumber: String(templateWithRenderedFiles.lockNumber),
+        }),
+      })
+    );
+
+    const iframes = document.querySelectorAll('iframe');
+    expect(iframes).toHaveLength(2);
+
+    const [shortIframe, longIframe] = iframes;
+
+    expect(shortIframe).toHaveAttribute(
+      'src',
+      `/templates/files/client-123/renders/${templateWithRenderedFiles.id}/short-form.pdf`
+    );
+
+    expect(longIframe).toHaveAttribute(
+      'src',
+      `/templates/files/client-123/renders/${templateWithRenderedFiles.id}/long-form.pdf`
+    );
+  });
+
+  it('matches snapshot', async () => {
+    const { asFragment } = render(
+      await Page({
+        params: Promise.resolve({
+          templateId: templateWithRenderedFiles.id,
+        }),
+        searchParams: Promise.resolve({
+          lockNumber: String(templateWithRenderedFiles.lockNumber),
+        }),
+      })
+    );
+
+    expect(asFragment()).toMatchSnapshot();
+  });
+});
diff --git a/frontend/src/__tests__/app/review-and-approve-letter-template/server-action.test.ts b/frontend/src/__tests__/app/review-and-approve-letter-template/server-action.test.ts
new file mode 100644
index 000000000..799166647
--- /dev/null
+++ b/frontend/src/__tests__/app/review-and-approve-letter-template/server-action.test.ts
@@ -0,0 +1,118 @@
+/**
+ * @jest-environment node
+ */
+import { reviewAndApproveLetterTemplateAction } from '@app/review-and-approve-letter-template/[templateId]/server-action';
+import { redirect } from 'next/navigation';
+import { approveTemplate } from '@utils/form-actions';
+
+jest.mock('next/navigation');
+jest.mock('@utils/form-actions');
+
+const redirectMock = jest.mocked(redirect);
+const approveTemplateMock = jest.mocked(approveTemplate);
+
+const validTemplateId = 'f47ac10b-58cc-4372-a567-0e02b2c3d479';
+
+describe('reviewAndApproveLetterTemplateAction', () => {
+  beforeEach(() => {
+    jest.resetAllMocks();
+  });
+
+  it('should call approveTemplate and redirect on valid form data', async () => {
+    approveTemplateMock.mockResolvedValueOnce({
+      id: validTemplateId,
+      clientId: 'client',
+      name: 'name',
+      templateStatus: 'PROOF_APPROVED',
+      templateType: 'LETTER',
+      createdAt: '2025-01-01T00:00:00Z',
+      updatedAt: '2025-01-01T00:00:00Z',
+      lockNumber: 2,
+      language: 'en',
+      letterType: 'x0',
+      letterVersion: 'AUTHORING',
+      files: {
+        docxTemplate: {
+          fileName: 'template.docx',
+          currentVersion: 'v1',
+          virusScanStatus: 'PASSED',
+        },
+        initialRender: {
+          status: 'RENDERED',
+          fileName: 'render.pdf',
+          currentVersion: 'v1',
+          pageCount: 2,
+        },
+      },
+    });
+
+    const formData = new FormData();
+    formData.append('templateId', validTemplateId);
+    formData.append('lockNumber', '1');
+
+    await reviewAndApproveLetterTemplateAction({}, formData);
+
+    expect(approveTemplateMock).toHaveBeenCalledWith(validTemplateId, 1);
+    expect(redirectMock).toHaveBeenCalledWith(
+      `/letter-template-approved/${validTemplateId}`
+    );
+  });
+
+  it('should return error state when templateId is missing', async () => {
+    const formData = new FormData();
+    formData.append('lockNumber', '1');
+
+    const result = await reviewAndApproveLetterTemplateAction({}, formData);
+
+    expect(result).toHaveProperty('errorState');
+    expect(approveTemplateMock).not.toHaveBeenCalled();
+    expect(redirectMock).not.toHaveBeenCalled();
+  });
+
+  it('should return error state when lockNumber is missing', async () => {
+    const formData = new FormData();
+    formData.append('templateId', validTemplateId);
+
+    const result = await reviewAndApproveLetterTemplateAction({}, formData);
+
+    expect(result).toHaveProperty('errorState');
+    expect(approveTemplateMock).not.toHaveBeenCalled();
+    expect(redirectMock).not.toHaveBeenCalled();
+  });
+
+  it('should return error state when lockNumber is invalid', async () => {
+    const formData = new FormData();
+    formData.append('templateId', validTemplateId);
+    formData.append('lockNumber', 'not-a-number');
+
+    const result = await reviewAndApproveLetterTemplateAction({}, formData);
+
+    expect(result).toHaveProperty('errorState');
+    expect(approveTemplateMock).not.toHaveBeenCalled();
+    expect(redirectMock).not.toHaveBeenCalled();
+  });
+
+  it('should return error state when templateId is empty', async () => {
+    const formData = new FormData();
+    formData.append('templateId', '');
+    formData.append('lockNumber', '1');
+
+    const result = await reviewAndApproveLetterTemplateAction({}, formData);
+
+    expect(result).toHaveProperty('errorState');
+    expect(approveTemplateMock).not.toHaveBeenCalled();
+    expect(redirectMock).not.toHaveBeenCalled();
+  });
+
+  it('should return error state when templateId is not a valid UUID', async () => {
+    const formData = new FormData();
+    formData.append('templateId', 'not-a-uuid');
+    formData.append('lockNumber', '1');
+
+    const result = await reviewAndApproveLetterTemplateAction({}, formData);
+
+    expect(result).toHaveProperty('errorState');
+    expect(approveTemplateMock).not.toHaveBeenCalled();
+    expect(redirectMock).not.toHaveBeenCalled();
+  });
+});
diff --git a/frontend/src/__tests__/components/forms/PreviewEmailTemplate/__snapshots__/PreviewEmailTemplate.test.tsx.snap b/frontend/src/__tests__/components/forms/PreviewEmailTemplate/__snapshots__/PreviewEmailTemplate.test.tsx.snap
index 48ffe055f..3be944f99 100644
--- a/frontend/src/__tests__/components/forms/PreviewEmailTemplate/__snapshots__/PreviewEmailTemplate.test.tsx.snap
+++ b/frontend/src/__tests__/components/forms/PreviewEmailTemplate/__snapshots__/PreviewEmailTemplate.test.tsx.snap
@@ -54,7 +54,6 @@ exports[`Preview email form renders Routing feature flag - Disabled Client-side
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-email
@@ -333,7 +332,6 @@ exports[`Preview email form renders Routing feature flag - Disabled matches erro
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-email
@@ -592,7 +590,6 @@ exports[`Preview email form renders matches snapshot when navigating from edit s
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-email
@@ -839,7 +836,6 @@ exports[`Preview email form renders matches snapshot when navigating from edit s
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-email
@@ -1005,7 +1001,6 @@ exports[`Preview email form renders matches snapshot when navigating from manage
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-email
@@ -1247,7 +1242,6 @@ exports[`Preview email form renders matches snapshot when navigating from manage
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-email
diff --git a/frontend/src/__tests__/components/forms/PreviewNHSAppTemplate/__snapshots__/PreviewNHSAppTemplate.test.tsx.snap b/frontend/src/__tests__/components/forms/PreviewNHSAppTemplate/__snapshots__/PreviewNHSAppTemplate.test.tsx.snap
index 9d8244090..86fb477eb 100644
--- a/frontend/src/__tests__/components/forms/PreviewNHSAppTemplate/__snapshots__/PreviewNHSAppTemplate.test.tsx.snap
+++ b/frontend/src/__tests__/components/forms/PreviewNHSAppTemplate/__snapshots__/PreviewNHSAppTemplate.test.tsx.snap
@@ -54,7 +54,6 @@ exports[`Preview nhs app form renders Routing feature flag - Disabled Client-sid
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-nhs app
@@ -309,7 +308,6 @@ exports[`Preview nhs app form renders Routing feature flag - Disabled matches er
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-nhs app
@@ -544,7 +542,6 @@ exports[`Preview nhs app form renders matches snapshot when navigating from edit
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-nhs app
@@ -767,7 +764,6 @@ exports[`Preview nhs app form renders matches snapshot when navigating from edit
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-nhs app
@@ -909,7 +905,6 @@ exports[`Preview nhs app form renders matches snapshot when navigating from mana
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-nhs app
@@ -1127,7 +1122,6 @@ exports[`Preview nhs app form renders matches snapshot when navigating from mana
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-nhs app
diff --git a/frontend/src/__tests__/components/forms/PreviewSMSTemplate/__snapshots__/PreviewSMSTemplate.test.tsx.snap b/frontend/src/__tests__/components/forms/PreviewSMSTemplate/__snapshots__/PreviewSMSTemplate.test.tsx.snap
index 4369f0a29..04fafb872 100644
--- a/frontend/src/__tests__/components/forms/PreviewSMSTemplate/__snapshots__/PreviewSMSTemplate.test.tsx.snap
+++ b/frontend/src/__tests__/components/forms/PreviewSMSTemplate/__snapshots__/PreviewSMSTemplate.test.tsx.snap
@@ -54,7 +54,6 @@ exports[`Review sms form renders Routing feature flag - Disabled Client-side val
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-sms
@@ -308,7 +307,6 @@ exports[`Review sms form renders Routing feature flag - Disabled matches error s
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-sms
@@ -542,7 +540,6 @@ exports[`Review sms form renders matches snapshot when navigating from edit scre
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-sms
@@ -764,7 +761,6 @@ exports[`Review sms form renders matches snapshot when navigating from edit scre
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-sms
@@ -905,7 +901,6 @@ exports[`Review sms form renders matches snapshot when navigating from manage te
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-sms
@@ -1122,7 +1117,6 @@ exports[`Review sms form renders matches snapshot when navigating from manage te
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             test-template-sms
diff --git a/frontend/src/__tests__/components/molecules/LetterRender/LetterRender.test.tsx b/frontend/src/__tests__/components/molecules/LetterRender/LetterRender.test.tsx
index 32935f212..b2a5d299d 100644
--- a/frontend/src/__tests__/components/molecules/LetterRender/LetterRender.test.tsx
+++ b/frontend/src/__tests__/components/molecules/LetterRender/LetterRender.test.tsx
@@ -82,6 +82,7 @@ describe('LetterRender', () => {
       'href',
       'https://notify.nhs.uk/using-nhs-notify/personalisation'
     );
+    expect(link).toHaveAttribute('target', '_blank');
   });
 
   it('matches snapshot', () => {
diff --git a/frontend/src/__tests__/components/molecules/LetterRender/LetterRenderIframe.test.tsx b/frontend/src/__tests__/components/molecules/LetterRender/LetterRenderIframe.test.tsx
index 2aa91a4a7..df4c3619f 100644
--- a/frontend/src/__tests__/components/molecules/LetterRender/LetterRenderIframe.test.tsx
+++ b/frontend/src/__tests__/components/molecules/LetterRender/LetterRenderIframe.test.tsx
@@ -19,6 +19,20 @@ describe('LetterRenderIframe', () => {
       );
     });
 
+    it('adds additional props', () => {
+      render(
+        <LetterRenderIframe
+          tab='longFormRender'
+          pdfUrl='/templates/files/client-123/renders/template-123/initial.pdf'
+          className='additional'
+        />
+      );
+
+      const iframe = screen.getByTitle('Letter preview - long examples');
+
+      expect(iframe).toHaveAttribute('class', 'additional');
+    });
+
     it('renders correct title for short tab', () => {
       render(<LetterRenderIframe tab='shortFormRender' pdfUrl='/test.pdf' />);
 
diff --git a/frontend/src/__tests__/components/molecules/LetterRender/__snapshots__/LetterRender.test.tsx.snap b/frontend/src/__tests__/components/molecules/LetterRender/__snapshots__/LetterRender.test.tsx.snap
index e614f3a34..06370e4cc 100644
--- a/frontend/src/__tests__/components/molecules/LetterRender/__snapshots__/LetterRender.test.tsx.snap
+++ b/frontend/src/__tests__/components/molecules/LetterRender/__snapshots__/LetterRender.test.tsx.snap
@@ -16,6 +16,8 @@ exports[`LetterRender matches snapshot 1`] = `
     <a
       class="nhsuk-body"
       href="https://notify.nhs.uk/using-nhs-notify/personalisation"
+      rel="noopener noreferrer"
+      target="_blank"
     >
       Learn more about personalising your letters (opens in a new tab).
     </a>
diff --git a/frontend/src/__tests__/components/molecules/PreviewTemplateDetails.test.tsx b/frontend/src/__tests__/components/molecules/PreviewTemplateDetails.test.tsx
index 01ad206ca..c660886da 100644
--- a/frontend/src/__tests__/components/molecules/PreviewTemplateDetails.test.tsx
+++ b/frontend/src/__tests__/components/molecules/PreviewTemplateDetails.test.tsx
@@ -459,15 +459,17 @@ describe('PreviewTemplateDetailsAuthoringLetter', () => {
 
   describe('sheets calculation', () => {
     it.each([
-      { pageCount: 1, expectedSheets: 1 },
-      { pageCount: 2, expectedSheets: 1 },
-      { pageCount: 3, expectedSheets: 2 },
-      { pageCount: 4, expectedSheets: 2 },
-      { pageCount: 5, expectedSheets: 3 },
-      { pageCount: 6, expectedSheets: 3 },
+      { pageCount: 1, bothSides: true, expectedSheets: 1 },
+      { pageCount: 2, bothSides: true, expectedSheets: 1 },
+      { pageCount: 3, bothSides: true, expectedSheets: 2 },
+      { pageCount: 4, bothSides: true, expectedSheets: 2 },
+      { pageCount: 5, bothSides: true, expectedSheets: 3 },
+      { pageCount: 6, bothSides: true, expectedSheets: 3 },
+      { pageCount: 1, bothSides: false, expectedSheets: 1 },
+      { pageCount: 6, bothSides: false, expectedSheets: 6 },
     ])(
-      'calculates sheets as $expectedSheets when pageCount is $pageCount',
-      ({ pageCount, expectedSheets }) => {
+      'calculates sheets as $expectedSheets when pageCount is $pageCount and bothSides is $bothSides',
+      ({ pageCount, bothSides, expectedSheets }) => {
         render(
           <PreviewTemplateDetailsAuthoringLetter
             template={{
@@ -486,6 +488,19 @@ describe('PreviewTemplateDetailsAuthoringLetter', () => {
                 },
               },
             }}
+            letterVariant={{
+              bothSides,
+              dispatchTime: '2026-03-16T14:51:43.884Z',
+              envelopeSize: 'C5',
+              id: 'variant-id',
+              maxSheets: 4,
+              name: 'test',
+              postage: 'first',
+              printColour: 'black',
+              sheetSize: 'A4',
+              status: 'PROD',
+              type: 'STANDARD',
+            }}
           />
         );
 
diff --git a/frontend/src/__tests__/components/molecules/__snapshots__/PreviewSubmittedTemplate.test.tsx.snap b/frontend/src/__tests__/components/molecules/__snapshots__/PreviewSubmittedTemplate.test.tsx.snap
index b7128b7e2..a99c10aa2 100644
--- a/frontend/src/__tests__/components/molecules/__snapshots__/PreviewSubmittedTemplate.test.tsx.snap
+++ b/frontend/src/__tests__/components/molecules/__snapshots__/PreviewSubmittedTemplate.test.tsx.snap
@@ -29,7 +29,6 @@ exports[`PreviewSubmittedTemplate component routing = false should render PDF le
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             Example letter
@@ -295,7 +294,6 @@ exports[`PreviewSubmittedTemplate component routing = false should render app me
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             Example template
@@ -440,7 +438,6 @@ exports[`PreviewSubmittedTemplate component routing = false should render author
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             Example authoring letter
@@ -654,7 +651,6 @@ exports[`PreviewSubmittedTemplate component routing = false should render email
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             Example Email template
@@ -824,7 +820,6 @@ exports[`PreviewSubmittedTemplate component routing = false should render sms 1`
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             SMS template
@@ -969,7 +964,6 @@ exports[`PreviewSubmittedTemplate component routing = true should render PDF let
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             Example letter
@@ -1232,7 +1226,6 @@ exports[`PreviewSubmittedTemplate component routing = true should render app mes
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             Example template
@@ -1392,7 +1385,6 @@ exports[`PreviewSubmittedTemplate component routing = true should render authori
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             Example authoring letter
@@ -1615,7 +1607,6 @@ exports[`PreviewSubmittedTemplate component routing = true should render email 1
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             Example Email template
@@ -1800,7 +1791,6 @@ exports[`PreviewSubmittedTemplate component routing = true should render sms 1`]
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             SMS template
diff --git a/frontend/src/__tests__/components/molecules/__snapshots__/PreviewTemplateDetails.test.tsx.snap b/frontend/src/__tests__/components/molecules/__snapshots__/PreviewTemplateDetails.test.tsx.snap
index 422b72fb2..1ef435267 100644
--- a/frontend/src/__tests__/components/molecules/__snapshots__/PreviewTemplateDetails.test.tsx.snap
+++ b/frontend/src/__tests__/components/molecules/__snapshots__/PreviewTemplateDetails.test.tsx.snap
@@ -11,7 +11,6 @@ exports[`PreviewTemplateDetailsAuthoringLetter snapshots matches snapshot 1`] =
       Template
     </span>
     <h1
-      class="preview__heading"
       data-testid="preview-message__heading"
     >
       Authoring Letter
@@ -230,7 +229,6 @@ exports[`PreviewTemplateDetailsAuthoringLetter snapshots matches snapshot with h
       Template
     </span>
     <h1
-      class="preview__heading"
       data-testid="preview-message__heading"
     >
       Authoring Letter
@@ -414,7 +412,6 @@ exports[`PreviewTemplateDetailsAuthoringLetter snapshots matches snapshot with i
       Template
     </span>
     <h1
-      class="preview__heading"
       data-testid="preview-message__heading"
     >
       Authoring Letter
@@ -585,7 +582,6 @@ exports[`PreviewTemplateDetailsAuthoringLetter snapshots matches snapshot with l
       Template
     </span>
     <h1
-      class="preview__heading"
       data-testid="preview-message__heading"
     >
       Authoring Letter
@@ -806,7 +802,6 @@ exports[`PreviewTemplateDetailsAuthoringLetter snapshots matches snapshot withou
       Template
     </span>
     <h1
-      class="preview__heading"
       data-testid="preview-message__heading"
     >
       Authoring Letter
@@ -1025,7 +1020,6 @@ exports[`PreviewTemplateDetailsEmail matches snapshot 1`] = `
       Template
     </span>
     <h1
-      class="preview__heading"
       data-testid="preview-message__heading"
     >
       Example Email template
@@ -1160,7 +1154,6 @@ exports[`PreviewTemplateDetailsNhsApp matches snapshot 1`] = `
       Template
     </span>
     <h1
-      class="preview__heading"
       data-testid="preview-message__heading"
     >
       Example template
@@ -1270,7 +1263,6 @@ exports[`PreviewTemplateDetailsPdfLetter matches snapshot when test data CSV is
       Template
     </span>
     <h1
-      class="preview__heading"
       data-testid="preview-message__heading"
     >
       PDF Letter
@@ -1383,7 +1375,6 @@ exports[`PreviewTemplateDetailsPdfLetter matches snapshot with proofs (failed vi
       Template
     </span>
     <h1
-      class="preview__heading"
       data-testid="preview-message__heading"
     >
       PDF Letter
@@ -1617,7 +1608,6 @@ exports[`PreviewTemplateDetailsPdfLetter matches snapshot without proofs 1`] = `
       Template
     </span>
     <h1
-      class="preview__heading"
       data-testid="preview-message__heading"
     >
       PDF Letter
@@ -1771,7 +1761,6 @@ exports[`PreviewTemplateDetailsSms matches snapshot 1`] = `
       Template
     </span>
     <h1
-      class="preview__heading"
       data-testid="preview-message__heading"
     >
       SMS template
diff --git a/frontend/src/__tests__/components/molecules/__snapshots__/PreviewTemplateFromMessagePlan.test.tsx.snap b/frontend/src/__tests__/components/molecules/__snapshots__/PreviewTemplateFromMessagePlan.test.tsx.snap
index 9123bcd31..ee69f8628 100644
--- a/frontend/src/__tests__/components/molecules/__snapshots__/PreviewTemplateFromMessagePlan.test.tsx.snap
+++ b/frontend/src/__tests__/components/molecules/__snapshots__/PreviewTemplateFromMessagePlan.test.tsx.snap
@@ -29,7 +29,6 @@ exports[`PreviewTemplateFromMessagePlan renders Authoring Letter template previe
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             authoring letter template name
@@ -202,7 +201,6 @@ exports[`PreviewTemplateFromMessagePlan renders Email template preview with the
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             email template name
@@ -345,7 +343,6 @@ exports[`PreviewTemplateFromMessagePlan renders French Letter template preview w
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             letter template name
@@ -466,7 +463,6 @@ exports[`PreviewTemplateFromMessagePlan renders Large Print Letter template prev
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             large print letter template name
@@ -587,7 +583,6 @@ exports[`PreviewTemplateFromMessagePlan renders NHS App template preview with th
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             app template name
@@ -705,7 +700,6 @@ exports[`PreviewTemplateFromMessagePlan renders PDF Letter template preview with
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             letter template name
@@ -826,7 +820,6 @@ exports[`PreviewTemplateFromMessagePlan renders SMS template preview with the co
             Template
           </span>
           <h1
-            class="preview__heading"
             data-testid="preview-message__heading"
           >
             sms template name
diff --git a/frontend/src/__tests__/utils/form-actions.test.ts b/frontend/src/__tests__/utils/form-actions.test.ts
index 09aafde50..d50f584f0 100644
--- a/frontend/src/__tests__/utils/form-actions.test.ts
+++ b/frontend/src/__tests__/utils/form-actions.test.ts
@@ -21,6 +21,7 @@ import {
   getLetterVariantsForTemplate,
   getLetterVariantById,
   uploadDocxTemplate,
+  approveTemplate,
   generateLetterProof,
 } from '@utils/form-actions';
 import { getSessionServer } from '@utils/amplify-utils';
@@ -894,6 +895,83 @@ describe('form-actions', () => {
     });
   });
 
+  describe('approveTemplate', () => {
+    test('approveTemplate successfully', async () => {
+      const responseData = {
+        id: 'id',
+        clientId: 'client-id',
+        templateType: 'LETTER',
+        templateStatus: 'PROOF_APPROVED',
+        name: 'name',
+        createdAt: '2025-01-13T10:19:25.579Z',
+        updatedAt: '2025-01-13T10:19:25.579Z',
+        lockNumber: 1,
+        language: 'en',
+        letterType: 'x0',
+        letterVersion: 'AUTHORING',
+        files: {
+          docxTemplate: {
+            fileName: 'template.docx',
+            currentVersion: 'v1',
+            virusScanStatus: 'PASSED',
+          },
+          initialRender: {
+            status: 'RENDERED',
+            fileName: 'render.pdf',
+            currentVersion: 'v1',
+            pageCount: 2,
+          },
+        },
+      } satisfies TemplateDto;
+
+      mockedTemplateClient.approveTemplate.mockResolvedValueOnce({
+        data: responseData,
+      });
+
+      const response = await approveTemplate('id', 0);
+
+      expect(mockedTemplateClient.approveTemplate).toHaveBeenCalledWith(
+        'id',
+        'token',
+        0
+      );
+
+      expect(response).toEqual(responseData);
+    });
+
+    test('approveTemplate - should throw error when saving unexpectedly fails', async () => {
+      mockedTemplateClient.approveTemplate.mockResolvedValueOnce({
+        error: {
+          errorMeta: {
+            code: 400,
+            description: 'Bad request',
+          },
+        },
+      });
+
+      await expect(approveTemplate('id', 0)).rejects.toThrow(
+        'Failed to approve template'
+      );
+
+      expect(mockedTemplateClient.approveTemplate).toHaveBeenCalledWith(
+        'id',
+        'token',
+        0
+      );
+    });
+
+    test('approveTemplate - should throw error when no token', async () => {
+      authIdTokenServerMock.mockResolvedValueOnce({
+        accessToken: undefined,
+        clientId: undefined,
+      });
+
+      await expect(approveTemplate('id', 0)).rejects.toThrow(
+        'Failed to get access token'
+      );
+    });
+  });
+
   describe('setTemplateToDeleted', () => {
     test('deleteTemplate successfully', async () => {
       mockedTemplateClient.deleteTemplate.mockResolvedValueOnce({
diff --git a/frontend/src/__tests__/utils/letter-render-url.test.ts b/frontend/src/__tests__/utils/letter-render-url.test.ts
new file mode 100644
index 000000000..bf7a54245
--- /dev/null
+++ b/frontend/src/__tests__/utils/letter-render-url.test.ts
@@ -0,0 +1,24 @@
+import { AUTHORING_LETTER_TEMPLATE } from '@testhelpers/helpers';
+import { buildLetterRenderUrl } from '@utils/letter-render-url';
+
+jest.mock('@utils/get-base-path', () => ({
+  getBasePath: jest.fn(() => '/templates'),
+}));
+
+const { getBasePath } = jest.requireMock('@utils/get-base-path');
+
+describe('buildLetterRenderUrl', () => {
+  it('builds the URL using basePath, clientId, template id, and fileName', () => {
+    expect(buildLetterRenderUrl(AUTHORING_LETTER_TEMPLATE, 'render.pdf')).toBe(
+      `/templates/files/${AUTHORING_LETTER_TEMPLATE.clientId}/renders/${AUTHORING_LETTER_TEMPLATE.id}/render.pdf`
+    );
+  });
+
+  it('uses the value returned by getBasePath', () => {
+    getBasePath.mockReturnValueOnce('/custom');
+
+    expect(buildLetterRenderUrl(AUTHORING_LETTER_TEMPLATE, 'file.pdf')).toBe(
+      `/custom/files/${AUTHORING_LETTER_TEMPLATE.clientId}/renders/${AUTHORING_LETTER_TEMPLATE.id}/file.pdf`
+    );
+  });
+});
diff --git a/frontend/src/app/preview-letter-template/[templateId]/page.tsx b/frontend/src/app/preview-letter-template/[templateId]/page.tsx
index dd7840dda..93ebeaa3f 100644
--- a/frontend/src/app/preview-letter-template/[templateId]/page.tsx
+++ b/frontend/src/app/preview-letter-template/[templateId]/page.tsx
@@ -15,8 +15,8 @@ import PreviewTemplateDetailsAuthoringLetter from '@molecules/PreviewTemplateDet
 import { PreviewPdfLetterTemplate } from '@organisms/PreviewPdfLetterTemplate/PreviewPdfLetterTemplate';
 import { PollLetterRender } from '@molecules/PollLetterRender/PollLetterRender';
 import { NHSNotifyFormProvider } from '@providers/form-provider';
-import { getLetterVariantById, getTemplate } from '@utils/form-actions';
 import { LetterRenderPollingProvider } from '@providers/letter-render-polling-provider';
+import { getLetterVariantById, getTemplate } from '@utils/form-actions';
 import { LetterSubmitButton } from '@molecules/LetterRender/LetterSubmitButton';
 import { submitAuthoringLetterAction } from './server-action';
 import content from '@content/content';
diff --git a/frontend/src/app/preview-letter-template/[templateId]/server-action.ts b/frontend/src/app/preview-letter-template/[templateId]/server-action.ts
index a5a1f2748..0fe45a302 100644
--- a/frontend/src/app/preview-letter-template/[templateId]/server-action.ts
+++ b/frontend/src/app/preview-letter-template/[templateId]/server-action.ts
@@ -24,6 +24,9 @@ export async function submitAuthoringLetterAction(
 
   const { templateId, lockNumber } = result.data;
 
-  // destination TBD
-  redirect(`/submit-letter-template/${templateId}?lockNumber=${lockNumber}`);
+  redirect(
+    // temporary destination
+    // TODO: CCM-14583 change to get ready to approve URL
+    `/review-and-approve-letter-template/${templateId}?lockNumber=${lockNumber}`
+  );
 }
diff --git a/frontend/src/app/review-and-approve-letter-template/[templateId]/ReviewAndApproveLetterTemplatePage.module.scss b/frontend/src/app/review-and-approve-letter-template/[templateId]/ReviewAndApproveLetterTemplatePage.module.scss
new file mode 100644
index 000000000..40769cbf3
--- /dev/null
+++ b/frontend/src/app/review-and-approve-letter-template/[templateId]/ReviewAndApproveLetterTemplatePage.module.scss
@@ -0,0 +1,4 @@
+.iframe {
+  width: 100%;
+  height: 1200px
+}
diff --git a/frontend/src/app/review-and-approve-letter-template/[templateId]/page.tsx b/frontend/src/app/review-and-approve-letter-template/[templateId]/page.tsx
new file mode 100644
index 000000000..254cff331
--- /dev/null
+++ b/frontend/src/app/review-and-approve-letter-template/[templateId]/page.tsx
@@ -0,0 +1,156 @@
+'use server';
+
+import { Metadata } from 'next';
+import { redirect, RedirectType } from 'next/navigation';
+import {
+  TemplatePageProps,
+  validateLetterTemplate,
+} from 'nhs-notify-web-template-management-utils';
+import { getLetterVariantById, getTemplate } from '@utils/form-actions';
+import content from '@content/content';
+import { NHSNotifyContainer } from '@layouts/container/container';
+import { NHSNotifyFormProvider } from '@providers/form-provider';
+import * as NHSNotifyForm from '@atoms/NHSNotifyForm';
+import { NHSNotifyMain } from '@atoms/NHSNotifyMain/NHSNotifyMain';
+import { reviewAndApproveLetterTemplateAction } from './server-action';
+import { PreviewTemplateDetailsAuthoringLetterTable } from '@molecules/PreviewTemplateDetails/PreviewTemplateDetailsAuthoringLetter';
+import { LetterRenderIframe } from '@molecules/LetterRender/LetterRenderIframe';
+import { getBasePath } from '@utils/get-base-path';
+import { NHSNotifyButton } from '@atoms/NHSNotifyButton/NHSNotifyButton';
+import styles from './ReviewAndApproveLetterTemplatePage.module.scss';
+import { interpolate } from '@utils/interpolate';
+import { $LockNumber } from 'nhs-notify-backend-client/schemas';
+import concatClassNames from '@utils/concat-class-names';
+import { buildLetterRenderUrl } from '@utils/letter-render-url';
+
+const {
+  pageTitle,
+  goBackButtonText,
+  goBackPath,
+  shortExampleHeading,
+  longExampleHeading,
+  submitText,
+  pageHeading,
+  headerCaption,
+} = content.pages.reviewAndApproveLetterTemplate;
+
+export async function generateMetadata(): Promise<Metadata> {
+  return {
+    title: pageTitle,
+  };
+}
+
+const ReviewAndApproveLetterTemplatePage = async (props: TemplatePageProps) => {
+  const { templateId } = await props.params;
+
+  const template = await getTemplate(templateId);
+
+  const validatedTemplate = validateLetterTemplate(template);
+
+  if (!validatedTemplate || validatedTemplate.letterVersion !== 'AUTHORING') {
+    return redirect('/invalid-template', RedirectType.replace);
+  }
+
+  const searchParams = await props.searchParams;
+
+  const lockNumberResult = $LockNumber.safeParse(searchParams?.lockNumber);
+
+  if (
+    !lockNumberResult.success ||
+    lockNumberResult.data !== validatedTemplate.lockNumber ||
+    // since lock number is unchanged, the following should never be true
+    !validatedTemplate.letterVariantId ||
+    validatedTemplate.files.longFormRender?.status !== 'RENDERED' ||
+    validatedTemplate.files.shortFormRender?.status !== 'RENDERED'
+  ) {
+    return redirect(
+      `/preview-letter-template/${templateId}`,
+      RedirectType.replace
+    );
+  }
+
+  const { longFormRender, shortFormRender } = validatedTemplate.files;
+
+  const letterVariant = await getLetterVariantById(
+    validatedTemplate.letterVariantId
+  );
+
+  return (
+    <NHSNotifyContainer>
+      <NHSNotifyMain>
+        <NHSNotifyFormProvider
+          serverAction={reviewAndApproveLetterTemplateAction}
+        >
+          <div className='nhsuk-u-reading-width'>
+            <span className='nhsuk-caption-l'>{headerCaption}</span>
+            <h1 data-testid='preview-message__heading'>
+              {interpolate(pageHeading, {
+                templateName: validatedTemplate.name,
+              })}
+            </h1>
+          </div>
+          <PreviewTemplateDetailsAuthoringLetterTable
+            template={validatedTemplate}
+            letterVariant={letterVariant}
+            hideEditActions
+            hideLearnMore
+          />
+          <h2 className='nhsuk-heading-m'>{shortExampleHeading}</h2>
+          <LetterRenderIframe
+            className={concatClassNames(
+              styles.iframe,
+              'nhsuk-u-margin-bottom-6'
+            )}
+            tab='shortFormRender'
+            pdfUrl={buildLetterRenderUrl(
+              validatedTemplate,
+              shortFormRender.fileName
+            )}
+          />
+          <h2 className='nhsuk-heading-m'>{longExampleHeading}</h2>
+          <LetterRenderIframe
+            className={concatClassNames(
+              styles.iframe,
+              'nhsuk-u-margin-bottom-6'
+            )}
+            tab='longFormRender'
+            pdfUrl={buildLetterRenderUrl(
+              validatedTemplate,
+              longFormRender.fileName
+            )}
+          />
+          <NHSNotifyForm.Form formId='review-and-approve-letter'>
+            <input
+              type='hidden'
+              name='templateId'
+              value={validatedTemplate.id}
+            />
+            <input
+              type='hidden'
+              name='lockNumber'
+              value={validatedTemplate.lockNumber}
+            />
+            <div className='nhsuk-form-group'>
+              <NHSNotifyButton type='submit'>{submitText}</NHSNotifyButton>
+
+              <NHSNotifyButton
+                secondary
+                id='go-back-button'
+                href={interpolate(goBackPath, {
+                  templateId: validatedTemplate.id,
+                  basePath: getBasePath(),
+                })}
+                data-testid='back-link-bottom'
+                className='nhsuk-u-margin-left-3'
+              >
+                {goBackButtonText}
+              </NHSNotifyButton>
+            </div>
+          </NHSNotifyForm.Form>
+        </NHSNotifyFormProvider>
+      </NHSNotifyMain>
+    </NHSNotifyContainer>
+  );
+};
+
+export default ReviewAndApproveLetterTemplatePage;
diff --git a/frontend/src/app/review-and-approve-letter-template/[templateId]/server-action.ts b/frontend/src/app/review-and-approve-letter-template/[templateId]/server-action.ts
new file mode 100644
index 000000000..fc623b1a2
--- /dev/null
+++ b/frontend/src/app/review-and-approve-letter-template/[templateId]/server-action.ts
@@ -0,0 +1,31 @@
+'use server';
+
+import { z } from 'zod/v4';
+import type { FormState } from 'nhs-notify-web-template-management-utils';
+import { redirect } from 'next/navigation';
+import { approveTemplate } from '@utils/form-actions';
+import { $LockNumber } from 'nhs-notify-backend-client/schemas';
+
+const $FormSchema = z.object({
+  templateId: z.uuidv4(),
+  lockNumber: $LockNumber,
+});
+
+export async function reviewAndApproveLetterTemplateAction(
+  _: FormState,
+  form: FormData
+): Promise<FormState> {
+  const result = $FormSchema.safeParse(Object.fromEntries(form.entries()));
+
+  if (result.error) {
+    return {
+      errorState: z.flattenError(result.error),
+    };
+  }
+
+  const { templateId, lockNumber } = result.data;
+
+  await approveTemplate(templateId, lockNumber);
+
+  redirect(`/letter-template-approved/${templateId}`);
+}
diff --git a/frontend/src/components/molecules/LetterRender/LetterRender.tsx b/frontend/src/components/molecules/LetterRender/LetterRender.tsx
index 8cc802466..433804566 100644
--- a/frontend/src/components/molecules/LetterRender/LetterRender.tsx
+++ b/frontend/src/components/molecules/LetterRender/LetterRender.tsx
@@ -17,7 +17,12 @@ export function LetterRender({
     <section className='nhsuk-u-margin-top-6'>
       <h2 className='nhsuk-heading-m'>{copy.heading}</h2>
       <p>{copy.guidance}</p>
-      <Link href={copy.guidanceLink.href} className='nhsuk-body'>
+      <Link
+        href={copy.guidanceLink.href}
+        className='nhsuk-body'
+        target='_blank'
+        rel='noopener noreferrer'
+      >
         {copy.guidanceLink.text}
       </Link>
 
diff --git a/frontend/src/components/molecules/LetterRender/LetterRenderIframe.tsx b/frontend/src/components/molecules/LetterRender/LetterRenderIframe.tsx
index 960e44ebb..3a114745e 100644
--- a/frontend/src/components/molecules/LetterRender/LetterRenderIframe.tsx
+++ b/frontend/src/components/molecules/LetterRender/LetterRenderIframe.tsx
@@ -3,9 +3,13 @@ import type { PersonalisedRenderKey } from '@utils/types';
 type LetterRenderIframeProps = {
   tab: PersonalisedRenderKey;
   pdfUrl: string | null;
-};
+} & React.ComponentProps<'iframe'>;
 
-export function LetterRenderIframe({ tab, pdfUrl }: LetterRenderIframeProps) {
+export function LetterRenderIframe({
+  tab,
+  pdfUrl,
+  ...rest
+}: LetterRenderIframeProps) {
   if (!pdfUrl) return <p className='nhsuk-body'>No preview available</p>;
   const tabDescription = tab === 'shortFormRender' ? 'short' : 'long';
 
@@ -14,6 +18,7 @@ export function LetterRenderIframe({ tab, pdfUrl }: LetterRenderIframeProps) {
       src={pdfUrl}
       title={`Letter preview - ${tabDescription} examples`}
       aria-label={`PDF preview of letter template with ${tabDescription} example personalisation data`}
+      {...rest}
     />
   );
 }
diff --git a/frontend/src/components/molecules/LetterRender/LetterRenderTab.tsx b/frontend/src/components/molecules/LetterRender/LetterRenderTab.tsx
index d34ac8e4d..548e904be 100644
--- a/frontend/src/components/molecules/LetterRender/LetterRenderTab.tsx
+++ b/frontend/src/components/molecules/LetterRender/LetterRenderTab.tsx
@@ -4,7 +4,6 @@ import type {
   AuthoringLetterTemplate,
   FormState,
 } from 'nhs-notify-web-template-management-utils';
-import { getBasePath } from '@utils/get-base-path';
 import {
   NHSNotifyFormProvider,
   useNHSNotifyForm,
@@ -18,6 +17,7 @@ import styles from './LetterRenderTab.module.scss';
 import { PollLetterRender } from '@molecules/PollLetterRender/PollLetterRender';
 import { PERSONALISATION_FORMDATA_PREFIX } from '@utils/constants';
 import content from '@content/content';
+import { buildLetterRenderUrl } from '@utils/letter-render-url';
 
 const { loadingText } = content.components.letterRender;
 
@@ -26,11 +26,6 @@ type LetterRenderTabProps = {
   tab: PersonalisedRenderKey;
 };
 
-function buildPdfUrl(template: AuthoringLetterTemplate, fileName: string) {
-  const basePath = getBasePath();
-  return `${basePath}/files/${template.clientId}/renders/${template.id}/${fileName}`;
-}
-
 function derivePdfUrl(
   template: AuthoringLetterTemplate,
   personalisedRender: RenderDetails | undefined
@@ -43,7 +38,7 @@ function derivePdfUrl(
       : initialRender;
 
   return render?.status === 'RENDERED'
-    ? buildPdfUrl(template, render.fileName)
+    ? buildLetterRenderUrl(template, render.fileName)
     : null;
 }
 
diff --git a/frontend/src/components/molecules/LetterRender/server-action.ts b/frontend/src/components/molecules/LetterRender/server-action.ts
index a6c6fb975..7045591de 100644
--- a/frontend/src/components/molecules/LetterRender/server-action.ts
+++ b/frontend/src/components/molecules/LetterRender/server-action.ts
@@ -9,11 +9,11 @@ import {
   SHORT_EXAMPLE_RECIPIENTS,
 } from '@content/example-recipients';
 import { formDataToFormStateFields } from '@utils/form-data-to-form-state';
-import { $LockNumber } from 'nhs-notify-backend-client/schemas';
 import { generateLetterProof } from '@utils/form-actions';
 import type { LetterProofRequest } from 'nhs-notify-web-template-management-types';
 import { PERSONALISATION_FORMDATA_PREFIX } from '@utils/constants';
 import { format as formatDate } from 'date-fns';
+import { $LockNumber } from 'nhs-notify-backend-client/schemas';
 
 const { pdsSection } = copy.components.letterRender;
 
diff --git a/frontend/src/components/molecules/PreviewTemplateDetails/PreviewTemplateDetailsAuthoringLetter.tsx b/frontend/src/components/molecules/PreviewTemplateDetails/PreviewTemplateDetailsAuthoringLetter.tsx
index 792b39af2..2d194c12a 100644
--- a/frontend/src/components/molecules/PreviewTemplateDetails/PreviewTemplateDetailsAuthoringLetter.tsx
+++ b/frontend/src/components/molecules/PreviewTemplateDetails/PreviewTemplateDetailsAuthoringLetter.tsx
@@ -21,35 +21,47 @@ import { toKebabCase } from '@utils/kebab-case';
 import styles from './PreviewTemplateDetails.module.scss';
 import { interpolate } from '@utils/interpolate';
 
+type PreviewTemplateDetailsAuthoringLetterProps = {
+  template: AuthoringLetterTemplate;
+  letterVariant?: LetterVariant;
+  hideStatus?: boolean;
+  hideEditActions?: boolean;
+  hideLearnMore?: boolean;
+};
+
 const { rowHeadings, visuallyHidden, externalLinks, actions, links } =
   content.components.previewTemplateDetails;
 
-function pagesAndSheetsCount(template: AuthoringLetterTemplate) {
+function pagesAndSheetsCount(
+  template: AuthoringLetterTemplate,
+  bothSides = true
+) {
   const pages =
     template.files.initialRender.status === 'RENDERED'
       ? template.files.initialRender.pageCount
       : 0;
 
-  const sheets = Math.ceil(pages / 2);
+  const pagesPerSheet = bothSides ? 2 : 1;
+
+  const sheets = Math.ceil(pages / pagesPerSheet);
 
   return { pages, sheets };
 }
 
-export default function PreviewTemplateDetailsAuthoringLetter({
+export function PreviewTemplateDetailsAuthoringLetterTable({
   template,
   letterVariant,
   hideStatus,
   hideEditActions,
-}: {
-  template: AuthoringLetterTemplate;
-  letterVariant?: LetterVariant;
-  hideStatus?: boolean;
-  hideEditActions?: boolean;
-}) {
+  hideLearnMore,
+}: PreviewTemplateDetailsAuthoringLetterProps) {
   const features = useFeatureFlags();
   const campaignIds = useCampaignIds();
 
-  const { pages, sheets } = pagesAndSheetsCount(template);
+  const { pages, sheets } = pagesAndSheetsCount(
+    template,
+    letterVariant?.bothSides
+  );
 
   const hasSingleCampaign = campaignIds.length === 1;
 
@@ -74,8 +86,6 @@ export default function PreviewTemplateDetailsAuthoringLetter({
 
   return (
     <>
-      <DetailsHeader templateName={template.name} />
-
       {!hideEditName && (
         <p className='nhsuk-u-margin-bottom-4'>
           <Link
@@ -166,6 +176,7 @@ export default function PreviewTemplateDetailsAuthoringLetter({
                 label={actions.learnMore}
                 visuallyHiddenText={visuallyHidden.sheets}
                 testId='sheets-action'
+                hidden={hideLearnMore}
                 external
               />
             </SummaryList.Row>
@@ -212,6 +223,7 @@ export default function PreviewTemplateDetailsAuthoringLetter({
                 label={actions.learnMore}
                 visuallyHiddenText={visuallyHidden.status}
                 testId='status-action'
+                hidden={hideLearnMore}
                 external
               />
             </SummaryList.Row>
@@ -221,3 +233,14 @@ export default function PreviewTemplateDetailsAuthoringLetter({
     </>
   );
 }
+
+export default function PreviewTemplateDetailsAuthoringLetter(
+  props: PreviewTemplateDetailsAuthoringLetterProps
+) {
+  return (
+    <>
+      <DetailsHeader templateName={props.template.name} />
+      <PreviewTemplateDetailsAuthoringLetterTable {...props} />
+    </>
+  );
+}
diff --git a/frontend/src/components/molecules/PreviewTemplateDetails/common.tsx b/frontend/src/components/molecules/PreviewTemplateDetails/common.tsx
index 2b28f927d..53dec7cf7 100644
--- a/frontend/src/components/molecules/PreviewTemplateDetails/common.tsx
+++ b/frontend/src/components/molecules/PreviewTemplateDetails/common.tsx
@@ -153,12 +153,7 @@ export function DetailsHeader({
   return (
     <div className='nhsuk-u-reading-width'>
       <span className='nhsuk-caption-l'>{headerCaption}</span>
-      <h1
-        data-testid='preview-message__heading'
-        className={styles.preview__heading}
-      >
-        {templateName}
-      </h1>
+      <h1 data-testid='preview-message__heading'>{templateName}</h1>
     </div>
   );
 }
diff --git a/frontend/src/content/content.ts b/frontend/src/content/content.ts
index 7e2d37b01..4be0bb59f 100644
--- a/frontend/src/content/content.ts
+++ b/frontend/src/content/content.ts
@@ -1796,6 +1796,18 @@ const reviewAndMoveToProduction = {
   },
 };
 
+const reviewAndApproveLetterTemplate = {
+  pageTitle: generatePageTitle('Review and approve letter template'),
+  goBackButtonText: 'Go back',
+  goBackPath:
+    '{{basePath}}/get-ready-to-approve-letter-template/{{templateId}}',
+  shortExampleHeading: 'Short example preview',
+  longExampleHeading: 'Long example preview',
+  submitText: 'Approve letter template',
+  pageHeading: `Review and approve '{{templateName}}'`,
+  headerCaption: 'Step 2 of 2',
+};
+
 const editTemplateNamePage = {
   pageTitle: generatePageTitle('Edit template name'),
   form: {
@@ -1950,6 +1962,7 @@ const content = {
     previewOtherLanguageLetterTemplate,
     previewStandardEnglishLetterTemplate,
     previewSubmittedLetterTemplate,
+    reviewAndApproveLetterTemplate,
     reviewAndMoveToProduction,
     submitLetterTemplate: submitLetterTemplatePage,
     uploadDocxLetterTemplatePage,
diff --git a/frontend/src/middleware.ts b/frontend/src/middleware.ts
index a7b5dc225..3ea295495 100644
--- a/frontend/src/middleware.ts
+++ b/frontend/src/middleware.ts
@@ -53,6 +53,7 @@ const protectedPaths = [
   /^\/preview-submitted-nhs-app-template\/[^/]+$/,
   /^\/preview-submitted-text-message-template\/[^/]+$/,
   /^\/preview-text-message-template\/[^/]+$/,
+  /^\/review-and-approve-letter-template\/[^/]+$/,
   /^\/request-proof-of-template\/[^/]+$/,
   /^\/submit-email-template\/[^/]+$/,
   /^\/submit-letter-template\/[^/]+$/,
diff --git a/frontend/src/utils/form-actions.ts b/frontend/src/utils/form-actions.ts
index da3524bbd..4c27e12dc 100644
--- a/frontend/src/utils/form-actions.ts
+++ b/frontend/src/utils/form-actions.ts
@@ -10,9 +10,9 @@ import type { TemplateFilter } from 'nhs-notify-backend-client/types';
 import type {
   CreateUpdateTemplate,
   LetterPatch,
-  LetterProofRequest,
   TemplateDto,
   LetterVariant,
+  LetterProofRequest,
 } from 'nhs-notify-web-template-management-types';
 import { logger } from 'nhs-notify-web-template-management-utils/logger';
 import { LetterTemplate } from 'nhs-notify-web-template-management-utils';
@@ -115,6 +115,30 @@ export async function saveTemplate(
   return data;
 }
 
+export async function approveTemplate(
+  templateId: string,
+  lockNumber: number
+): Promise<TemplateDto> {
+  const { accessToken } = await getSessionServer();
+
+  if (!accessToken) {
+    throw new Error('Failed to get access token');
+  }
+
+  const { data, error } = await templateApiClient.approveTemplate(
+    templateId,
+    accessToken,
+    lockNumber
+  );
+
+  if (error) {
+    logger.error('Failed to approve template', error);
+    throw new Error('Failed to approve template');
+  }
+
+  return data;
+}
+
 export async function patchTemplate(
   templateId: string,
   template: LetterPatch,
diff --git a/frontend/src/utils/letter-render-url.ts b/frontend/src/utils/letter-render-url.ts
new file mode 100644
index 000000000..f687e6360
--- /dev/null
+++ b/frontend/src/utils/letter-render-url.ts
@@ -0,0 +1,10 @@
+import { AuthoringLetterTemplate } from '../../../utils/utils/src/types';
+import { getBasePath } from './get-base-path';
+
+export function buildLetterRenderUrl(
+  template: AuthoringLetterTemplate,
+  fileName: string
+) {
+  const basePath = getBasePath();
+  return `${basePath}/files/${template.clientId}/renders/${template.id}/${fileName}`;
+}
diff --git a/infrastructure/terraform/modules/backend-api/README.md b/infrastructure/terraform/modules/backend-api/README.md
index 1fc4bbb9f..565790689 100644
--- a/infrastructure/terraform/modules/backend-api/README.md
+++ b/infrastructure/terraform/modules/backend-api/README.md
@@ -39,6 +39,7 @@ No requirements.
 
 | Name | Source | Version |
 |------|--------|---------|
+| <a name="module_approve_template_lambda"></a> [approve\_template\_lambda](#module\_approve\_template\_lambda) | https://github.com/NHSDigital/nhs-notify-shared-modules/releases/download/3.0.6/terraform-lambda.zip | n/a |
 | <a name="module_authorizer_lambda"></a> [authorizer\_lambda](#module\_authorizer\_lambda) | https://github.com/NHSDigital/nhs-notify-shared-modules/releases/download/v2.0.29/terraform-lambda.zip | n/a |
 | <a name="module_count_routing_configs_lambda"></a> [count\_routing\_configs\_lambda](#module\_count\_routing\_configs\_lambda) | https://github.com/NHSDigital/nhs-notify-shared-modules/releases/download/v2.0.29/terraform-lambda.zip | n/a |
 | <a name="module_create_routing_config_lambda"></a> [create\_routing\_config\_lambda](#module\_create\_routing\_config\_lambda) | https://github.com/NHSDigital/nhs-notify-shared-modules/releases/download/v2.0.29/terraform-lambda.zip | n/a |
diff --git a/infrastructure/terraform/modules/backend-api/iam_role_api_gateway_execution_role.tf b/infrastructure/terraform/modules/backend-api/iam_role_api_gateway_execution_role.tf
index f8211cab3..2a1215ab1 100644
--- a/infrastructure/terraform/modules/backend-api/iam_role_api_gateway_execution_role.tf
+++ b/infrastructure/terraform/modules/backend-api/iam_role_api_gateway_execution_role.tf
@@ -48,6 +48,7 @@ data "aws_iam_policy_document" "api_gateway_execution_policy" {
     ]
 
     resources = [
+      module.approve_template_lambda.function_arn,
       module.authorizer_lambda.function_arn,
       module.upload_docx_letter_template_lambda.function_arn,
       module.upload_letter_template_lambda.function_arn,
diff --git a/infrastructure/terraform/modules/backend-api/locals.tf b/infrastructure/terraform/modules/backend-api/locals.tf
index c472b8714..7445fd49f 100644
--- a/infrastructure/terraform/modules/backend-api/locals.tf
+++ b/infrastructure/terraform/modules/backend-api/locals.tf
@@ -12,6 +12,7 @@ locals {
 
   openapi_spec = templatefile("${path.module}/spec.tmpl.json", {
     APIG_EXECUTION_ROLE_ARN                       = aws_iam_role.api_gateway_execution_role.arn
+    APPROVE_TEMPLATE_LAMBDA_ARN                   = module.approve_template_lambda.function_arn
     AUTHORIZER_LAMBDA_ARN                         = module.authorizer_lambda.function_arn
     AWS_REGION                                    = var.region
     COUNT_ROUTING_CONFIGS_LAMBDA_ARN              = module.count_routing_configs_lambda.function_arn
diff --git a/infrastructure/terraform/modules/backend-api/module_approve_template_lambda.tf b/infrastructure/terraform/modules/backend-api/module_approve_template_lambda.tf
new file mode 100644
index 000000000..7d02fcb55
--- /dev/null
+++ b/infrastructure/terraform/modules/backend-api/module_approve_template_lambda.tf
@@ -0,0 +1,81 @@
+module "approve_template_lambda" {
+  source = "https://github.com/NHSDigital/nhs-notify-shared-modules/releases/download/3.0.6/terraform-lambda.zip"
+
+  project        = var.project
+  environment    = var.environment
+  component      = var.component
+  aws_account_id = var.aws_account_id
+  region         = var.region
+
+  kms_key_arn = var.kms_key_arn
+
+  function_name = "approve-template"
+
+  function_module_name  = "approve-template"
+  handler_function_name = "handler"
+  description           = "Approve a template"
+
+  memory  = 2048
+  timeout = 20
+  runtime = "nodejs22.x"
+
+  log_retention_in_days = var.log_retention_in_days
+  iam_policy_document = {
+    body = data.aws_iam_policy_document.approve_template_lambda_policy.json
+  }
+
+  lambda_env_vars         = local.backend_lambda_environment_variables
+  function_s3_bucket      = var.function_s3_bucket
+  function_code_base_path = local.lambdas_dir
+  function_code_dir       = "backend-api/dist/approve-template"
+
+  send_to_firehose          = var.send_to_firehose
+  log_destination_arn       = var.log_destination_arn
+  log_subscription_role_arn = var.log_subscription_role_arn
+}
+
+data "aws_iam_policy_document" "approve_template_lambda_policy" {
+  statement {
+    sid    = "AllowTemplatesReadWrite"
+    effect = "Allow"
+
+    actions = [
+      "dynamodb:GetItem",
+      "dynamodb:UpdateItem",
+    ]
+
+    resources = [
+      aws_dynamodb_table.templates.arn,
+    ]
+  }
+
+  statement {
+    sid    = "AllowGetLetterVariants"
+    effect = "Allow"
+
+    actions = [
+      "dynamodb:GetItem",
+    ]
+
+    resources = [
+      aws_dynamodb_table.letter_variants.arn,
+    ]
+  }
+
+  statement {
+    sid    = "AllowKMSAccess"
+    effect = "Allow"
+
+    actions = [
+      "kms:Decrypt",
+      "kms:DescribeKey",
+      "kms:Encrypt",
+      "kms:GenerateDataKey*",
+      "kms:ReEncrypt*",
+    ]
+
+    resources = [
+      var.kms_key_arn
+    ]
+  }
+}
diff --git a/infrastructure/terraform/modules/backend-api/spec.tmpl.json b/infrastructure/terraform/modules/backend-api/spec.tmpl.json
index a29fe0cd7..1097f0e24 100644
--- a/infrastructure/terraform/modules/backend-api/spec.tmpl.json
+++ b/infrastructure/terraform/modules/backend-api/spec.tmpl.json
@@ -2511,6 +2511,80 @@
         }
       }
     },
+    "/v1/template/{templateId}/approve": {
+      "patch": {
+        "description": "Approve a template by Id",
+        "parameters": [
+          {
+            "description": "ID of template to approve",
+            "in": "path",
+            "name": "templateId",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          },
+          {
+            "description": "Lock number of the current version of the template",
+            "in": "header",
+            "name": "X-Lock-Number",
+            "required": true,
+            "schema": {
+              "type": "integer"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/TemplateSuccess"
+                }
+              }
+            },
+            "description": "200 response",
+            "headers": {
+              "Content-Type": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            }
+          },
+          "default": {
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/Failure"
+                }
+              }
+            },
+            "description": "Error"
+          }
+        },
+        "security": [
+          {
+            "authorizer": []
+          }
+        ],
+        "summary": "Approve a template",
+        "x-amazon-apigateway-integration": {
+          "contentHandling": "CONVERT_TO_TEXT",
+          "credentials": "${APIG_EXECUTION_ROLE_ARN}",
+          "httpMethod": "POST",
+          "passthroughBehavior": "WHEN_NO_TEMPLATES",
+          "responses": {
+            ".*": {
+              "statusCode": "200"
+            }
+          },
+          "timeoutInMillis": 29000,
+          "type": "AWS_PROXY",
+          "uri": "arn:aws:apigateway:${AWS_REGION}:lambda:path/2015-03-31/functions/${APPROVE_TEMPLATE_LAMBDA_ARN}/invocations"
+        }
+      }
+    },
     "/v1/template/{templateId}/generate-letter-proof": {
       "post": {
         "description": "Generate a personalised letter proof",
diff --git a/lambdas/backend-api/README.md b/lambdas/backend-api/README.md
index ecd5ffcb8..cafdcc6a9 100644
--- a/lambdas/backend-api/README.md
+++ b/lambdas/backend-api/README.md
@@ -67,6 +67,16 @@ curl -X PATCH --location "${APIG_STAGE}/v1/template/${TEMPLATE_ID}" \
 }'
 ```
 
+### PATCH - /v1/template/:templateId/approve - Approve a letter template
+
+```bash
+curl -X PATCH --location "${APIG_STAGE}/v1/template/${TEMPLATE_ID}/approve" \
+--header 'Content-Type: application/json' \
+--header 'Accept: application/json' \
+--header "Authorization: $SANDBOX_TOKEN" \
+--header "X-Lock-Number: $CURRENT_LOCK_NUMBER"
+```
+
 ### GET - /v1/templates - Get all templates
 
 currently limited to 50 items
diff --git a/lambdas/backend-api/build.sh b/lambdas/backend-api/build.sh
index 4532e0ab2..834f0fbbf 100755
--- a/lambdas/backend-api/build.sh
+++ b/lambdas/backend-api/build.sh
@@ -14,6 +14,7 @@ npx esbuild \
     --entry-names=[name]/[name] \
     --outdir=dist \
     --external:pdfjs-dist \
+    src/approve-template.ts \
     src/copy-scanned-object-to-internal.ts \
     src/count-routing-configs.ts \
     src/create-routing-config.ts \
diff --git a/lambdas/backend-api/src/__tests__/api/approve-template.test.ts b/lambdas/backend-api/src/__tests__/api/approve-template.test.ts
new file mode 100644
index 000000000..f634f44c9
--- /dev/null
+++ b/lambdas/backend-api/src/__tests__/api/approve-template.test.ts
@@ -0,0 +1,272 @@
+import type { APIGatewayProxyEvent, Context } from 'aws-lambda';
+import { mock } from 'jest-mock-extended';
+import type { TemplateDto } from 'nhs-notify-web-template-management-types';
+import { createHandler } from '../../api/approve-template';
+import { TemplateClient } from '../../app/template-client';
+
+const setup = () => {
+  const templateClient = mock<TemplateClient>();
+
+  const handler = createHandler({ templateClient });
+
+  return { handler, mocks: { templateClient } };
+};
+
+describe('Template API - Approve', () => {
+  beforeEach(jest.resetAllMocks);
+
+  test.each([
+    ['undefined', undefined],
+    ['missing user', { clientId: 'client-id', internalUserId: undefined }],
+    ['missing client', { clientId: undefined, internalUserId: 'user-1234' }],
+  ])(
+    'should return 400 - Invalid request when requestContext is %s',
+    async (_, ctx) => {
+      const { handler, mocks } = setup();
+
+      const event = mock<APIGatewayProxyEvent>({
+        requestContext: { authorizer: ctx },
+        pathParameters: { templateId: 'id' },
+        headers: { 'X-Lock-Number': '0' },
+      });
+
+      const result = await handler(event, mock<Context>(), jest.fn());
+
+      expect(result).toEqual({
+        statusCode: 400,
+        body: JSON.stringify({
+          statusCode: 400,
+          technicalMessage: 'Invalid request',
+        }),
+      });
+
+      expect(mocks.templateClient.approveTemplate).not.toHaveBeenCalled();
+    }
+  );
+
+  test('should return 400 - Invalid request when, no templateId', async () => {
+    const { handler, mocks } = setup();
+
+    const event = mock<APIGatewayProxyEvent>({
+      requestContext: {
+        authorizer: {
+          internalUserId: 'user-1234',
+          clientId: 'nhs-notify-client-id',
+        },
+      },
+      pathParameters: { templateId: undefined },
+      headers: { 'X-Lock-Number': '0' },
+    });
+
+    const result = await handler(event, mock<Context>(), jest.fn());
+
+    expect(result).toEqual({
+      statusCode: 400,
+      body: JSON.stringify({
+        statusCode: 400,
+        technicalMessage: 'Invalid request',
+      }),
+    });
+
+    expect(mocks.templateClient.approveTemplate).not.toHaveBeenCalled();
+  });
+
+  test('should return error when approving template fails', async () => {
+    const { handler, mocks } = setup();
+
+    mocks.templateClient.approveTemplate.mockResolvedValueOnce({
+      error: {
+        errorMeta: {
+          code: 500,
+          description: 'Internal server error',
+        },
+      },
+    });
+
+    const event = mock<APIGatewayProxyEvent>({
+      requestContext: {
+        authorizer: {
+          internalUserId: 'user-1234',
+          clientId: 'nhs-notify-client-id',
+        },
+      },
+      pathParameters: { templateId: '1-2-3' },
+      headers: { 'X-Lock-Number': '0' },
+    });
+
+    const result = await handler(event, mock<Context>(), jest.fn());
+
+    expect(result).toEqual({
+      statusCode: 500,
+      body: JSON.stringify({
+        statusCode: 500,
+        technicalMessage: 'Internal server error',
+      }),
+    });
+
+    expect(mocks.templateClient.approveTemplate).toHaveBeenCalledWith(
+      '1-2-3',
+      {
+        internalUserId: 'user-1234',
+        clientId: 'nhs-notify-client-id',
+      },
+      '0'
+    );
+  });
+
+  test('should return error with details when approving template fails with details', async () => {
+    const { handler, mocks } = setup();
+
+    mocks.templateClient.approveTemplate.mockResolvedValueOnce({
+      error: {
+        errorMeta: {
+          code: 400,
+          description: 'Template cannot be approved',
+          details: { reason: 'not a letter' },
+        },
+      },
+    });
+
+    const event = mock<APIGatewayProxyEvent>({
+      requestContext: {
+        authorizer: {
+          internalUserId: 'user-1234',
+          clientId: 'nhs-notify-client-id',
+        },
+      },
+      pathParameters: { templateId: '1-2-3' },
+      headers: { 'X-Lock-Number': '1' },
+    });
+
+    const result = await handler(event, mock<Context>(), jest.fn());
+
+    expect(result).toEqual({
+      statusCode: 400,
+      body: JSON.stringify({
+        statusCode: 400,
+        technicalMessage: 'Template cannot be approved',
+        details: { reason: 'not a letter' },
+      }),
+    });
+  });
+
+  test('should coerce missing lock number header to empty string', async () => {
+    const { handler, mocks } = setup();
+
+    mocks.templateClient.approveTemplate.mockResolvedValueOnce({
+      error: {
+        errorMeta: {
+          code: 409,
+          description:
+            'Lock number mismatch - Template has been modified since last read',
+        },
+      },
+    });
+
+    const event = mock<APIGatewayProxyEvent>({
+      requestContext: {
+        authorizer: {
+          internalUserId: 'user-1234',
+          clientId: 'nhs-notify-client-id',
+        },
+      },
+      pathParameters: { templateId: '1-2-3' },
+      headers: {},
+    });
+
+    const result = await handler(event, mock<Context>(), jest.fn());
+
+    expect(result).toEqual({
+      statusCode: 409,
+      body: JSON.stringify({
+        statusCode: 409,
+        technicalMessage:
+          'Lock number mismatch - Template has been modified since last read',
+      }),
+    });
+
+    expect(mocks.templateClient.approveTemplate).toHaveBeenCalledWith(
+      '1-2-3',
+      {
+        internalUserId: 'user-1234',
+        clientId: 'nhs-notify-client-id',
+      },
+      ''
+    );
+  });
+
+  test('should return template on success', async () => {
+    const { handler, mocks } = setup();
+
+    const response: TemplateDto = {
+      id: '1-2-3',
+      clientId: 'clientid',
+      name: 'approved-template',
+      templateStatus: 'PROOF_APPROVED',
+      templateType: 'LETTER',
+      createdAt: new Date().toISOString(),
+      updatedAt: new Date().toISOString(),
+      lockNumber: 1,
+      language: 'en',
+      letterType: 'x0',
+      letterVersion: 'AUTHORING',
+      letterVariantId: 'var1',
+      files: {
+        docxTemplate: {
+          fileName: 'template.docx',
+          currentVersion: 'v1',
+          virusScanStatus: 'PASSED',
+        },
+        initialRender: {
+          status: 'RENDERED',
+          fileName: 'render.pdf',
+          currentVersion: 'v1',
+          pageCount: 2,
+        },
+        shortFormRender: {
+          status: 'RENDERED',
+          fileName: 'render1.pdf',
+          currentVersion: 'v1',
+          pageCount: 2,
+        },
+        longFormRender: {
+          status: 'RENDERED',
+          fileName: 'render2.pdf',
+          currentVersion: 'v1',
+          pageCount: 2,
+        },
+      },
+    };
+
+    mocks.templateClient.approveTemplate.mockResolvedValueOnce({
+      data: response,
+    });
+
+    const event = mock<APIGatewayProxyEvent>({
+      requestContext: {
+        authorizer: {
+          internalUserId: 'user-1234',
+          clientId: 'nhs-notify-client-id',
+        },
+      },
+      pathParameters: { templateId: '1-2-3' },
+      headers: { 'X-Lock-Number': '0' },
+    });
+
+    const result = await handler(event, mock<Context>(), jest.fn());
+
+    expect(result).toEqual({
+      statusCode: 200,
+      body: JSON.stringify({ statusCode: 200, data: response }),
+    });
+
+    expect(mocks.templateClient.approveTemplate).toHaveBeenCalledWith(
+      '1-2-3',
+      {
+        internalUserId: 'user-1234',
+        clientId: 'nhs-notify-client-id',
+      },
+      '0'
+    );
+  });
+});
diff --git a/lambdas/backend-api/src/__tests__/app/letter-variant-client.test.ts b/lambdas/backend-api/src/__tests__/app/letter-variant-client.test.ts
index 25b4dbf63..7bae7bd69 100644
--- a/lambdas/backend-api/src/__tests__/app/letter-variant-client.test.ts
+++ b/lambdas/backend-api/src/__tests__/app/letter-variant-client.test.ts
@@ -105,7 +105,7 @@ test('it returns the 404 if the found variant belongs to a different client', as
 
   expect(result).toEqual({
     error: {
-      errorMeta: { code: 404, description: 'Letter Variant not found' },
+      errorMeta: { code: 404, description: 'Letter variant not found' },
     },
   });
 });
diff --git a/lambdas/backend-api/src/__tests__/app/template-client.test.ts b/lambdas/backend-api/src/__tests__/app/template-client.test.ts
index dd13ffa63..0f1ef4101 100644
--- a/lambdas/backend-api/src/__tests__/app/template-client.test.ts
+++ b/lambdas/backend-api/src/__tests__/app/template-client.test.ts
@@ -4292,6 +4292,513 @@ describe('templateClient', () => {
     });
   });
 
+  describe('approveTemplate', () => {
+    const letterVariantId = 'variant-1';
+
+    const allRenderedFiles: AuthoringLetterFiles = {
+      docxTemplate: {
+        fileName: 'template.docx',
+        currentVersion: 'v1',
+        virusScanStatus: 'PASSED',
+      },
+      initialRender: {
+        status: 'RENDERED',
+        fileName: 'render.pdf',
+        currentVersion: 'v1',
+        pageCount: 2,
+      },
+      shortFormRender: {
+        status: 'RENDERED',
+        fileName: 'short.pdf',
+        currentVersion: 'v1',
+        pageCount: 1,
+      },
+      longFormRender: {
+        status: 'RENDERED',
+        fileName: 'long.pdf',
+        currentVersion: 'v1',
+        pageCount: 3,
+      },
+    };
+
+    const notYetSubmittedLetterDto: TemplateDto = {
+      id: templateId,
+      clientId: 'client',
+      createdAt: new Date().toISOString(),
+      updatedAt: new Date().toISOString(),
+      templateStatus: 'NOT_YET_SUBMITTED',
+      name: 'name',
+      templateType: 'LETTER',
+      lockNumber: 1,
+      language: 'en',
+      letterType: 'x0',
+      letterVersion: 'AUTHORING',
+      campaignId: 'campaign-1',
+      letterVariantId,
+      files: allRenderedFiles,
+    };
+
+    const letterVariant: LetterVariant = {
+      id: letterVariantId,
+      name: 'Standard C5',
+      sheetSize: 'A4',
+      maxSheets: 5,
+      bothSides: true,
+      printColour: 'black',
+      envelopeSize: 'C5',
+      dispatchTime: 'standard',
+      postage: 'economy',
+      status: 'PROD',
+      type: 'STANDARD',
+    };
+
+    const dbTemplate = {
+      ...notYetSubmittedLetterDto,
+      owner: `CLIENT#${user.clientId}`,
+      version: 1,
+    };
+
+    test('returns failure result when lock number is invalid', async () => {
+      const { templateClient, mocks } = setup();
+
+      const result = await templateClient.approveTemplate(templateId, user, '');
+
+      expect(
+        mocks.templateRepository.approveLetterTemplate
+      ).not.toHaveBeenCalled();
+
+      expect(result).toEqual({
+        error: {
+          errorMeta: {
+            code: 400,
+            description: 'Invalid lock number provided',
+          },
+        },
+      });
+    });
+
+    test('returns failure result when GET template fails', async () => {
+      const { templateClient, mocks } = setup();
+
+      mocks.templateRepository.get.mockResolvedValueOnce({
+        error: {
+          errorMeta: {
+            code: 500,
+            description: 'Internal server error',
+          },
+        },
+      });
+
+      const result = await templateClient.approveTemplate(
+        templateId,
+        user,
+        '0'
+      );
+
+      expect(mocks.templateRepository.get).toHaveBeenCalledWith(
+        templateId,
+        user.clientId
+      );
+      expect(
+        mocks.templateRepository.approveLetterTemplate
+      ).not.toHaveBeenCalled();
+
+      expect(result).toEqual({
+        error: {
+          errorMeta: {
+            code: 500,
+            description: 'Internal server error',
+          },
+        },
+      });
+    });
+
+    test.each([
+      {
+        scenario: 'template is not a LETTER',
+        override: { templateType: 'EMAIL' as const, letterVersion: undefined },
+      },
+      {
+        scenario: 'template is not AUTHORING',
+        override: { letterVersion: 'PDF' as const },
+      },
+      {
+        scenario: 'template is not NOT_YET_SUBMITTED',
+        override: { templateStatus: 'SUBMITTED' as const },
+      },
+      {
+        scenario: 'template has no campaignId',
+        override: { campaignId: undefined },
+      },
+      {
+        scenario: 'template has no letterVariantId',
+        override: { letterVariantId: undefined },
+      },
+    ])('returns 400 when $scenario', async ({ override }) => {
+      const { templateClient, mocks } = setup();
+
+      mocks.templateRepository.get.mockResolvedValueOnce({
+        data: {
+          ...dbTemplate,
+          ...override,
+        },
+      });
+
+      const result = await templateClient.approveTemplate(
+        templateId,
+        user,
+        '0'
+      );
+
+      expect(
+        mocks.templateRepository.approveLetterTemplate
+      ).not.toHaveBeenCalled();
+
+      expect(result).toEqual({
+        error: {
+          errorMeta: {
+            code: 400,
+            description: 'Template cannot be approved',
+          },
+        },
+      });
+    });
+
+    test('returns failure result when letter variant fetch fails', async () => {
+      const { templateClient, mocks } = setup();
+
+      mocks.templateRepository.get.mockResolvedValueOnce({
+        data: dbTemplate,
+      });
+
+      mocks.letterVariantRepository.getById.mockResolvedValueOnce({
+        error: {
+          errorMeta: {
+            code: 404,
+            description: 'Letter variant not found',
+          },
+        },
+      });
+
+      const result = await templateClient.approveTemplate(
+        templateId,
+        user,
+        '0'
+      );
+
+      expect(mocks.letterVariantRepository.getById).toHaveBeenCalledWith(
+        letterVariantId
+      );
+      expect(
+        mocks.templateRepository.approveLetterTemplate
+      ).not.toHaveBeenCalled();
+
+      expect(result).toEqual({
+        error: {
+          errorMeta: {
+            code: 404,
+            description: 'Letter variant not found',
+          },
+        },
+      });
+    });
+
+    test.each([
+      {
+        scenario: 'shortFormRender is missing',
+        files: {
+          ...allRenderedFiles,
+          shortFormRender: undefined,
+        },
+      },
+      {
+        scenario: 'longFormRender is missing',
+        files: {
+          ...allRenderedFiles,
+          longFormRender: undefined,
+        },
+      },
+      {
+        scenario: 'longFormRender is PENDING',
+        files: {
+          ...allRenderedFiles,
+          longFormRender: {
+            status: 'PENDING' as const,
+            requestedAt: NOW,
+          },
+        },
+      },
+      {
+        scenario: 'shortFormRender is PENDING',
+        files: {
+          ...allRenderedFiles,
+          shortFormRender: {
+            status: 'PENDING' as const,
+            requestedAt: NOW,
+          },
+        },
+      },
+    ])(
+      'returns 400 due to problems with renders: $scenario',
+      async ({ files }) => {
+        const { templateClient, mocks } = setup();
+
+        mocks.templateRepository.get.mockResolvedValueOnce({
+          data: {
+            ...dbTemplate,
+            files,
+          },
+        });
+
+        mocks.letterVariantRepository.getById.mockResolvedValueOnce({
+          data: letterVariant,
+        });
+
+        const result = await templateClient.approveTemplate(
+          templateId,
+          user,
+          '0'
+        );
+
+        expect(
+          mocks.templateRepository.approveLetterTemplate
+        ).not.toHaveBeenCalled();
+
+        expect(result).toEqual({
+          error: {
+            errorMeta: {
+              code: 400,
+              description:
+                'One or more personalised rendered example has not been generated',
+            },
+          },
+        });
+      }
+    );
+
+    test('returns 400 when sheet count exceeds maxSheets (variant has double-sided printing)', async () => {
+      const { templateClient, mocks } = setup();
+
+      const variantWith2Sheets: LetterVariant = {
+        ...letterVariant,
+        bothSides: true,
+        maxSheets: 2,
+      };
+
+      const filesWithTooManyPages: AuthoringLetterFiles = {
+        ...allRenderedFiles,
+        longFormRender: {
+          status: 'RENDERED',
+          fileName: 'long.pdf',
+          currentVersion: 'v1',
+          pageCount: 5,
+        },
+      };
+
+      mocks.templateRepository.get.mockResolvedValueOnce({
+        data: {
+          ...dbTemplate,
+          files: filesWithTooManyPages,
+        },
+      });
+
+      mocks.letterVariantRepository.getById.mockResolvedValueOnce({
+        data: variantWith2Sheets,
+      });
+
+      const result = await templateClient.approveTemplate(
+        templateId,
+        user,
+        '0'
+      );
+
+      expect(
+        mocks.templateRepository.approveLetterTemplate
+      ).not.toHaveBeenCalled();
+
+      expect(result).toEqual({
+        error: {
+          errorMeta: {
+            code: 400,
+            description:
+              'Letter template exceeded maximum number of sheets allowed by letter variant',
+          },
+        },
+      });
+    });
+
+    test('returns 400 when sheet count exceeds maxSheets (variant has single-sided printing)', async () => {
+      const { templateClient, mocks } = setup();
+
+      const variantSingleSided: LetterVariant = {
+        ...letterVariant,
+        bothSides: false,
+        maxSheets: 2,
+      };
+
+      const filesWithTooManyPages: AuthoringLetterFiles = {
+        ...allRenderedFiles,
+        longFormRender: {
+          status: 'RENDERED',
+          fileName: 'long.pdf',
+          currentVersion: 'v1',
+          pageCount: 3,
+        },
+      };
+
+      mocks.templateRepository.get.mockResolvedValueOnce({
+        data: {
+          ...dbTemplate,
+          files: filesWithTooManyPages,
+        },
+      });
+
+      mocks.letterVariantRepository.getById.mockResolvedValueOnce({
+        data: variantSingleSided,
+      });
+
+      const result = await templateClient.approveTemplate(
+        templateId,
+        user,
+        '0'
+      );
+
+      expect(
+        mocks.templateRepository.approveLetterTemplate
+      ).not.toHaveBeenCalled();
+
+      expect(result).toEqual({
+        error: {
+          errorMeta: {
+            code: 400,
+            description:
+              'Letter template exceeded maximum number of sheets allowed by letter variant',
+          },
+        },
+      });
+    });
+
+    test('should return a failure result when saving to the database fails', async () => {
+      const { templateClient, mocks } = setup();
+
+      mocks.templateRepository.get.mockResolvedValueOnce({
+        data: dbTemplate,
+      });
+
+      mocks.letterVariantRepository.getById.mockResolvedValueOnce({
+        data: letterVariant,
+      });
+
+      mocks.templateRepository.approveLetterTemplate.mockResolvedValueOnce({
+        error: {
+          errorMeta: {
+            code: 500,
+            description: 'Internal server error',
+          },
+        },
+      });
+
+      const result = await templateClient.approveTemplate(
+        templateId,
+        user,
+        '0'
+      );
+
+      expect(
+        mocks.templateRepository.approveLetterTemplate
+      ).toHaveBeenCalledWith(templateId, user, 0);
+
+      expect(result).toEqual({
+        error: {
+          errorMeta: {
+            code: 500,
+            description: 'Internal server error',
+          },
+        },
+      });
+    });
+
+    test('should return a failure result when updated database template is invalid', async () => {
+      const { templateClient, mocks } = setup();
+
+      const template: DatabaseTemplate = {
+        ...notYetSubmittedLetterDto,
+        createdAt: undefined as unknown as string,
+        owner: `CLIENT#${user.clientId}`,
+        version: 1,
+      };
+
+      mocks.templateRepository.get.mockResolvedValueOnce({
+        data: dbTemplate,
+      });
+
+      mocks.letterVariantRepository.getById.mockResolvedValueOnce({
+        data: letterVariant,
+      });
+
+      mocks.templateRepository.approveLetterTemplate.mockResolvedValueOnce({
+        data: template,
+      });
+
+      const result = await templateClient.approveTemplate(
+        templateId,
+        user,
+        '0'
+      );
+
+      expect(
+        mocks.templateRepository.approveLetterTemplate
+      ).toHaveBeenCalledWith(templateId, user, 0);
+
+      expect(result).toEqual({
+        error: {
+          errorMeta: {
+            code: 500,
+            description: 'Error retrieving template',
+          },
+        },
+      });
+    });
+
+    test('should return template updated to PROOF_APPROVED', async () => {
+      const { templateClient, mocks } = setup();
+
+      mocks.templateRepository.get.mockResolvedValueOnce({
+        data: dbTemplate,
+      });
+
+      mocks.letterVariantRepository.getById.mockResolvedValueOnce({
+        data: letterVariant,
+      });
+
+      mocks.templateRepository.approveLetterTemplate.mockResolvedValueOnce({
+        data: {
+          ...notYetSubmittedLetterDto,
+          templateStatus: 'PROOF_APPROVED',
+          owner: `CLIENT#${user.clientId}`,
+          version: 1,
+        },
+      });
+
+      const result = await templateClient.approveTemplate(
+        templateId,
+        user,
+        '0'
+      );
+
+      expect(
+        mocks.templateRepository.approveLetterTemplate
+      ).toHaveBeenCalledWith(templateId, user, 0);
+
+      expect(result).toEqual({
+        data: {
+          ...notYetSubmittedLetterDto,
+          templateStatus: 'PROOF_APPROVED',
+        },
+      });
+    });
+  });
+
   describe('requestProof', () => {
     test('returns failure result when lock number is invalid', async () => {
       const { templateClient, mocks } = setup();
diff --git a/lambdas/backend-api/src/__tests__/infra/letter-variant-repository.test.ts b/lambdas/backend-api/src/__tests__/infra/letter-variant-repository.test.ts
index e53f8cbf8..332fb96d8 100644
--- a/lambdas/backend-api/src/__tests__/infra/letter-variant-repository.test.ts
+++ b/lambdas/backend-api/src/__tests__/infra/letter-variant-repository.test.ts
@@ -168,7 +168,7 @@ describe('LetterVariantRepository', () => {
         error: {
           errorMeta: {
             code: ErrorCase.NOT_FOUND,
-            description: 'Letter Variant not found',
+            description: 'Letter variant not found',
             details: undefined,
           },
           actualError: undefined,
diff --git a/lambdas/backend-api/src/__tests__/infra/template-repository/repository.test.ts b/lambdas/backend-api/src/__tests__/infra/template-repository/repository.test.ts
index c85077397..dca64dd4a 100644
--- a/lambdas/backend-api/src/__tests__/infra/template-repository/repository.test.ts
+++ b/lambdas/backend-api/src/__tests__/infra/template-repository/repository.test.ts
@@ -1086,6 +1086,149 @@ describe('templateRepository', () => {
     });
   });
 
+  describe('approveLetterTemplate', () => {
+    test.each([
+      {
+        testName: 'When template does not exist',
+        Item: undefined,
+        code: 404,
+        message: 'Template not found',
+        returnActualError: false,
+      },
+      {
+        testName: 'Fails when template status is DELETED',
+        Item: marshall({
+          templateType: 'LETTER',
+          templateStatus: 'DELETED',
+          lockNumber: 0,
+        }),
+        code: 404,
+        message: 'Template not found',
+        returnActualError: false,
+      },
+      {
+        testName: 'Fails when stored lock number differs from input',
+        Item: marshall({
+          templateType: 'LETTER',
+          templateStatus: 'NOT_YET_SUBMITTED',
+          lockNumber: 1,
+        }),
+        code: 409,
+        message:
+          'Lock number mismatch - Template has been modified since last read',
+        returnActualError: true,
+      },
+      {
+        // lock number is currently the only condition, so this case is not expected
+        testName:
+          'Fails when template cannot be approved (condition check fails for other reasons)',
+        Item: marshall({
+          templateType: 'LETTER',
+          templateStatus: 'SUBMITTED',
+          lockNumber: 0,
+        }),
+        code: 400,
+        message: 'Template cannot be approved',
+        returnActualError: true,
+      },
+    ])(
+      'approveLetterTemplate: $testName',
+      async ({ Item, code, message, returnActualError }) => {
+        const { templateRepository, mocks } = setup();
+
+        const error = new ConditionalCheckFailedException({
+          message: 'mocked',
+          $metadata: { httpStatusCode: 400 },
+          Item,
+        });
+
+        mocks.ddbDocClient.on(UpdateCommand).rejects(error);
+
+        const response = await templateRepository.approveLetterTemplate(
+          'abc-def-ghi-jkl-123',
+          user,
+          0
+        );
+
+        expect(response).toEqual({
+          error: {
+            ...(returnActualError ? { actualError: error } : {}),
+            errorMeta: {
+              code,
+              description: message,
+            },
+          },
+        });
+      }
+    );
+
+    test('should return error when an unexpected error occurs', async () => {
+      const { templateRepository, mocks } = setup();
+
+      const error = new Error('mocked');
+
+      mocks.ddbDocClient.on(UpdateCommand).rejects(error);
+
+      const response = await templateRepository.approveLetterTemplate(
+        'abc-def-ghi-jkl-123',
+        user,
+        0
+      );
+
+      expect(response).toEqual({
+        error: {
+          actualError: error,
+          errorMeta: {
+            code: 500,
+            description: 'Failed to update template',
+          },
+        },
+      });
+    });
+
+    test('should update template status to PROOF_APPROVED', async () => {
+      const { templateRepository, mocks } = setup();
+      const id = 'abc-def-ghi-jkl-123';
+
+      const databaseTemplate: DatabaseTemplate = {
+        id,
+        owner: ownerWithClientPrefix,
+        version: 1,
+        name: 'updated-name',
+        message: 'updated-message',
+        templateStatus: 'PROOF_APPROVED',
+        templateType: 'LETTER',
+        updatedAt: 'now',
+        createdAt: 'yesterday',
+        lockNumber: 1,
+      };
+
+      mocks.ddbDocClient
+        .on(UpdateCommand, {
+          TableName: templatesTableName,
+          Key: { id, owner: ownerWithClientPrefix },
+        })
+        .resolves({ Attributes: databaseTemplate });
+
+      const response = await templateRepository.approveLetterTemplate(
+        id,
+        user,
+        0
+      );
+
+      expect(response).toEqual({
+        data: databaseTemplate,
+      });
+
+      expect(mocks.ddbDocClient).toHaveReceivedCommandWith(UpdateCommand, {
+        TableName: 'templates',
+        Key: { id: 'abc-def-ghi-jkl-123', owner: 'CLIENT#client-id' },
+        ReturnValues: 'ALL_NEW',
+        ReturnValuesOnConditionCheckFailure: 'ALL_OLD',
+      });
+    });
+  });
+
   describe('approveProof', () => {
     test('should update template status to PROOF_APPROVED', async () => {
       const { templateRepository, mocks } = setup();
diff --git a/lambdas/backend-api/src/api/approve-template.ts b/lambdas/backend-api/src/api/approve-template.ts
new file mode 100644
index 000000000..a0dd6aec7
--- /dev/null
+++ b/lambdas/backend-api/src/api/approve-template.ts
@@ -0,0 +1,39 @@
+import type { APIGatewayProxyHandler } from 'aws-lambda';
+import { apiFailure, apiSuccess } from '@backend-api/api/responses';
+import type { TemplateClient } from '@backend-api/app/template-client';
+import { toHeaders } from '@backend-api/utils/headers';
+
+export function createHandler({
+  templateClient,
+}: {
+  templateClient: TemplateClient;
+}): APIGatewayProxyHandler {
+  return async function (event) {
+    const { internalUserId, clientId } = event.requestContext.authorizer ?? {};
+
+    const templateId = event.pathParameters?.templateId;
+
+    if (!internalUserId || !templateId || !clientId) {
+      return apiFailure(400, 'Invalid request');
+    }
+
+    const { data, error } = await templateClient.approveTemplate(
+      templateId,
+      {
+        internalUserId,
+        clientId,
+      },
+      toHeaders(event.headers).get('X-Lock-Number') ?? ''
+    );
+
+    if (error) {
+      return apiFailure(
+        error.errorMeta.code,
+        error.errorMeta.description,
+        error.errorMeta.details
+      );
+    }
+
+    return apiSuccess(200, data);
+  };
+}
diff --git a/lambdas/backend-api/src/app/letter-variant-client.ts b/lambdas/backend-api/src/app/letter-variant-client.ts
index ea1f74253..ce3f41bf4 100644
--- a/lambdas/backend-api/src/app/letter-variant-client.ts
+++ b/lambdas/backend-api/src/app/letter-variant-client.ts
@@ -17,7 +17,7 @@ export class LetterVariantClient {
     const { data: variant } = result;
 
     if (variant.clientId && variant.clientId !== user.clientId) {
-      return failure(ErrorCase.NOT_FOUND, 'Letter Variant not found');
+      return failure(ErrorCase.NOT_FOUND, 'Letter variant not found');
     }
 
     return success(variant);
diff --git a/lambdas/backend-api/src/app/template-client.ts b/lambdas/backend-api/src/app/template-client.ts
index 24fb9183d..8ddf6a296 100644
--- a/lambdas/backend-api/src/app/template-client.ts
+++ b/lambdas/backend-api/src/app/template-client.ts
@@ -513,6 +513,108 @@ export class TemplateClient {
     return success(templateDTO);
   }
 
+  async approveTemplate(
+    templateId: string,
+    user: User,
+    lockNumber: string
+  ): Promise<Result<TemplateDto>> {
+    const log = this.logger.child({ templateId, user });
+
+    const lockNumberValidation = this.validateLockNumber(lockNumber, log);
+
+    if (lockNumberValidation.error) {
+      return lockNumberValidation;
+    }
+
+    const { data: template, error: getTemplateError } =
+      await this.templateRepository.get(templateId, user.clientId);
+
+    if (getTemplateError) {
+      log
+        .child(getTemplateError.errorMeta)
+        .error('Failed to get template', getTemplateError.actualError);
+
+      return { error: getTemplateError };
+    }
+
+    if (
+      template.templateType !== 'LETTER' ||
+      template.letterVersion !== 'AUTHORING' ||
+      template.templateStatus !== 'NOT_YET_SUBMITTED' ||
+      !template.campaignId ||
+      !template.letterVariantId
+    ) {
+      return failure(
+        ErrorCase.VALIDATION_FAILED,
+        'Template cannot be approved'
+      );
+    }
+
+    const { data: variant, error: getVariantError } =
+      await this.letterVariantRepository.getById(template.letterVariantId);
+
+    if (getVariantError) {
+      log
+        .child({
+          ...getVariantError.errorMeta,
+          letterVariantId: template.letterVariantId,
+        })
+        .error('Failed to get letter variant', getVariantError.actualError);
+
+      return { error: getVariantError };
+    }
+
+    const { initialRender, shortFormRender, longFormRender } =
+      template.files as AuthoringLetterFiles;
+
+    const pageCounts = [initialRender, shortFormRender, longFormRender].flatMap(
+      (r) => (r?.status === 'RENDERED' ? [r.pageCount] : [])
+    );
+
+    if (pageCounts.length !== 3) {
+      return failure(
+        ErrorCase.VALIDATION_FAILED,
+        'One or more personalised rendered example has not been generated'
+      );
+    }
+
+    const pagesPerSheet = variant.bothSides ? 2 : 1;
+
+    if (
+      pageCounts.some((c) => Math.ceil(c / pagesPerSheet) > variant.maxSheets)
+    ) {
+      return failure(
+        ErrorCase.VALIDATION_FAILED,
+        'Letter template exceeded maximum number of sheets allowed by letter variant'
+      );
+    }
+
+    const updateResult = await this.templateRepository.approveLetterTemplate(
+      templateId,
+      user,
+      lockNumberValidation.data
+    );
+
+    if (updateResult.error) {
+      log
+        .child(updateResult.error.errorMeta)
+        .error(
+          'Failed to save template to the database',
+          updateResult.error.actualError
+        );
+
+      return updateResult;
+    }
+
+    const templateDTO = this.mapDatabaseObjectToDTO(updateResult.data);
+
+    if (!templateDTO) {
+      return failure(ErrorCase.INTERNAL, 'Error retrieving template');
+    }
+
+    return success(templateDTO);
+  }
+
   async submitTemplate(
     templateId: string,
     user: User,
diff --git a/lambdas/backend-api/src/approve-template.ts b/lambdas/backend-api/src/approve-template.ts
new file mode 100644
index 000000000..223df3391
--- /dev/null
+++ b/lambdas/backend-api/src/approve-template.ts
@@ -0,0 +1,4 @@
+import { createHandler } from './api/approve-template';
+import { templatesContainer } from './container/templates';
+
+export const handler = createHandler(templatesContainer());
diff --git a/lambdas/backend-api/src/infra/letter-variant-repository/repository.ts b/lambdas/backend-api/src/infra/letter-variant-repository/repository.ts
index aa3d51384..a4a40c809 100644
--- a/lambdas/backend-api/src/infra/letter-variant-repository/repository.ts
+++ b/lambdas/backend-api/src/infra/letter-variant-repository/repository.ts
@@ -89,7 +89,7 @@ export class LetterVariantRepository {
       );
 
       if (!Item) {
-        return failure(ErrorCase.NOT_FOUND, 'Letter Variant not found');
+        return failure(ErrorCase.NOT_FOUND, 'Letter variant not found');
       }
 
       const variant = $LetterVariant.parse(Item);
diff --git a/lambdas/backend-api/src/infra/template-repository/repository.ts b/lambdas/backend-api/src/infra/template-repository/repository.ts
index 4c61fa0a2..2a46c0251 100644
--- a/lambdas/backend-api/src/infra/template-repository/repository.ts
+++ b/lambdas/backend-api/src/infra/template-repository/repository.ts
@@ -343,6 +343,60 @@ export class TemplateRepository {
     }
   }
 
+  async approveLetterTemplate(
+    templateId: string,
+    user: User,
+    lockNumber: number
+  ) {
+    const update = new TemplateUpdateBuilder(
+      this.templatesTableName,
+      user.clientId,
+      templateId,
+      {
+        ReturnValuesOnConditionCheckFailure: 'ALL_OLD',
+        ReturnValues: 'ALL_NEW',
+      }
+    )
+      .setStatus('PROOF_APPROVED')
+      .setUpdatedByUserAt(this.internalUserKey(user))
+      .incrementLockNumber()
+      // template is validated for submission in the template-client layer
+      .expectLockNumber(lockNumber)
+      .build();
+
+    try {
+      const response = await this.client.send(new UpdateCommand(update));
+      return success(response.Attributes as DatabaseTemplate);
+    } catch (error) {
+      if (error instanceof ConditionalCheckFailedException) {
+        if (!error.Item || error.Item.templateStatus.S === 'DELETED') {
+          return failure(ErrorCase.NOT_FOUND, 'Template not found');
+        }
+
+        const oldItem = unmarshall(error.Item);
+
+        if (oldItem.lockNumber !== lockNumber) {
+          return failure(
+            ErrorCase.CONFLICT,
+            'Lock number mismatch - Template has been modified since last read',
+            error
+          );
+        }
+
+        return failure(
+          ErrorCase.VALIDATION_FAILED,
+          'Template cannot be approved',
+          error
+        );
+      }
+
+      return failure(ErrorCase.INTERNAL, 'Failed to update template', error);
+    }
+  }
+
+  /**
+   * @deprecated - PDF letter only
+   */
   async approveProof(templateId: string, user: User, lockNumber: number) {
     const updateExpression = ['#templateStatus = :newStatus'];
 
diff --git a/lambdas/backend-client/src/__tests__/template-api-client.test.ts b/lambdas/backend-client/src/__tests__/template-api-client.test.ts
index 77eefceed..09be5f1bd 100644
--- a/lambdas/backend-client/src/__tests__/template-api-client.test.ts
+++ b/lambdas/backend-client/src/__tests__/template-api-client.test.ts
@@ -542,6 +542,58 @@ describe('TemplateAPIClient', () => {
     });
   });
 
+  describe('approveTemplate', () => {
+    test('should return error', async () => {
+      axiosMock.onPatch('/v1/template/real-id/approve').reply(400, {
+        statusCode: 400,
+        technicalMessage: 'Bad request',
+        details: {
+          message: 'Template cannot be approved',
+        },
+      });
+
+      const result = await client.approveTemplate('real-id', testToken, 2);
+
+      expect(result.error).toEqual({
+        errorMeta: {
+          code: 400,
+          description: 'Bad request',
+          details: {
+            message: 'Template cannot be approved',
+          },
+        },
+      });
+
+      expect(result.data).toBeUndefined();
+
+      expect(axiosMock.history.patch.length).toBe(1);
+
+      const headers = axiosMock.history.at(0)?.headers;
+
+      expect(headers ? headers['X-Lock-Number'] : null).toEqual('2');
+    });
+
+    test('should return template', async () => {
+      const data = {
+        id: 'real-id',
+        name: 'name',
+        templateStatus: 'PROOF_APPROVED',
+        templateType: 'LETTER',
+      };
+
+      axiosMock.onPatch('/v1/template/real-id/approve').reply(200, {
+        statusCode: 200,
+        data,
+      });
+
+      const result = await client.approveTemplate('real-id', testToken, 2);
+
+      expect(result.data).toEqual(data);
+
+      expect(result.error).toBeUndefined();
+    });
+  });
+
   describe('deleteTemplate', () => {
     test('should return error', async () => {
       axiosMock.onDelete('/v1/template/real-id').reply(400, {
diff --git a/lambdas/backend-client/src/template-api-client.ts b/lambdas/backend-client/src/template-api-client.ts
index 136380b0d..5c71d93f2 100644
--- a/lambdas/backend-client/src/template-api-client.ts
+++ b/lambdas/backend-client/src/template-api-client.ts
@@ -203,6 +203,36 @@ export const templateApiClient = {
     };
   },
 
+  async approveTemplate(
+    templateId: string,
+    owner: string,
+    lockNumber: number
+  ): Promise<Result<TemplateDto>> {
+    const response = await catchAxiosError(
+      httpClient.patch<TemplateSuccess>(
+        `/v1/template/${templateId}/approve`,
+        undefined,
+        {
+          headers: {
+            'Content-Type': 'application/json',
+            Authorization: owner,
+            'X-Lock-Number': String(lockNumber),
+          },
+        }
+      )
+    );
+
+    if (response.error) {
+      return {
+        error: response.error,
+      };
+    }
+
+    return {
+      data: response.data.data,
+    };
+  },
+
   async submitTemplate(
     templateId: string,
     owner: string,
diff --git a/package-lock.json b/package-lock.json
index 3f0763848..8b47fc44d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -7707,13 +7707,13 @@
       }
     },
     "node_modules/@aws-sdk/credential-provider-login": {
-      "version": "3.972.20",
-      "resolved": "https://registry.npmjs.org/@aws-sdk/credential-provider-login/-/credential-provider-login-3.972.20.tgz",
-      "integrity": "sha512-gEWo54nfqp2jABMu6HNsjVC4hDLpg9HC8IKSJnp0kqWtxIJYHTmiLSsIfI4ScQjxEwpB+jOOH8dOLax1+hy/Hw==",
+      "version": "3.972.21",
+      "resolved": "https://registry.npmjs.org/@aws-sdk/credential-provider-login/-/credential-provider-login-3.972.21.tgz",
+      "integrity": "sha512-ENU+YCiuQocQjfIf9bPxZ+ZY0wIBkl3SMH22optBQwy8UFpSfonHynXzGT27xQxer4cYTNOpwDqbfo57BusbpQ==",
       "license": "Apache-2.0",
       "dependencies": {
-        "@aws-sdk/core": "^3.973.20",
-        "@aws-sdk/nested-clients": "^3.996.10",
+        "@aws-sdk/core": "^3.973.21",
+        "@aws-sdk/nested-clients": "^3.996.11",
         "@aws-sdk/types": "^3.973.6",
         "@smithy/property-provider": "^4.2.12",
         "@smithy/protocol-http": "^5.3.12",
@@ -7726,19 +7726,19 @@
       }
     },
     "node_modules/@aws-sdk/credential-provider-login/node_modules/@aws-sdk/core": {
-      "version": "3.973.20",
-      "resolved": "https://registry.npmjs.org/@aws-sdk/core/-/core-3.973.20.tgz",
-      "integrity": "sha512-i3GuX+lowD892F3IuJf8o6AbyDupMTdyTxQrCJGcn71ni5hTZ82L4nQhcdumxZ7XPJRJJVHS/CR3uYOIIs0PVA==",
+      "version": "3.973.21",
+      "resolved": "https://registry.npmjs.org/@aws-sdk/core/-/core-3.973.21.tgz",
+      "integrity": "sha512-OTUcDX9Yfz/FLKbHjiMaP9D4Hs44lYJzN7zBcrK2nDmBt0Wr8D6nYt12QoBkZsW0nVMFsTIGaZCrsU9zCcIMXQ==",
       "license": "Apache-2.0",
       "dependencies": {
         "@aws-sdk/types": "^3.973.6",
-        "@aws-sdk/xml-builder": "^3.972.11",
-        "@smithy/core": "^3.23.11",
+        "@aws-sdk/xml-builder": "^3.972.12",
+        "@smithy/core": "^3.23.12",
         "@smithy/node-config-provider": "^4.3.12",
         "@smithy/property-provider": "^4.2.12",
         "@smithy/protocol-http": "^5.3.12",
         "@smithy/signature-v4": "^5.3.12",
-        "@smithy/smithy-client": "^4.12.5",
+        "@smithy/smithy-client": "^4.12.6",
         "@smithy/types": "^4.13.1",
         "@smithy/util-base64": "^4.3.2",
         "@smithy/util-middleware": "^4.2.12",
@@ -7795,15 +7795,15 @@
       }
     },
     "node_modules/@aws-sdk/credential-provider-login/node_modules/@aws-sdk/middleware-user-agent": {
-      "version": "3.972.21",
-      "resolved": "https://registry.npmjs.org/@aws-sdk/middleware-user-agent/-/middleware-user-agent-3.972.21.tgz",
-      "integrity": "sha512-62XRl1GDYPpkt7cx1AX1SPy9wgNE9Iw/NPuurJu4lmhCWS7sGKO+kS53TQ8eRmIxy3skmvNInnk0ZbWrU5Dpyg==",
+      "version": "3.972.22",
+      "resolved": "https://registry.npmjs.org/@aws-sdk/middleware-user-agent/-/middleware-user-agent-3.972.22.tgz",
+      "integrity": "sha512-pZPNGWZVQvgUIO/P9PXZNz7ciq9mLYb/wQEurg3phKTa3DiBIunIRcgA0eBNwmog6S3oy0KR1bv4EJ4ld9A5sQ==",
       "license": "Apache-2.0",
       "dependencies": {
-        "@aws-sdk/core": "^3.973.20",
+        "@aws-sdk/core": "^3.973.21",
         "@aws-sdk/types": "^3.973.6",
         "@aws-sdk/util-endpoints": "^3.996.5",
-        "@smithy/core": "^3.23.11",
+        "@smithy/core": "^3.23.12",
         "@smithy/protocol-http": "^5.3.12",
         "@smithy/types": "^4.13.1",
         "@smithy/util-retry": "^4.2.12",
@@ -7814,44 +7814,44 @@
       }
     },
     "node_modules/@aws-sdk/credential-provider-login/node_modules/@aws-sdk/nested-clients": {
-      "version": "3.996.10",
-      "resolved": "https://registry.npmjs.org/@aws-sdk/nested-clients/-/nested-clients-3.996.10.tgz",
-      "integrity": "sha512-SlDol5Z+C7Ivnc2rKGqiqfSUmUZzY1qHfVs9myt/nxVwswgfpjdKahyTzLTx802Zfq0NFRs7AejwKzzzl5Co2w==",
+      "version": "3.996.11",
+      "resolved": "https://registry.npmjs.org/@aws-sdk/nested-clients/-/nested-clients-3.996.11.tgz",
+      "integrity": "sha512-i7SwoSR4JB/79JoGDUACnFUQOZwXGLWNX35lIb1Pq72nUGlVV+RFZp+BLa8S+mog2pbXU9+6Kc5YwGiMi5bKhQ==",
       "license": "Apache-2.0",
       "dependencies": {
         "@aws-crypto/sha256-browser": "5.2.0",
         "@aws-crypto/sha256-js": "5.2.0",
-        "@aws-sdk/core": "^3.973.20",
+        "@aws-sdk/core": "^3.973.21",
         "@aws-sdk/middleware-host-header": "^3.972.8",
         "@aws-sdk/middleware-logger": "^3.972.8",
         "@aws-sdk/middleware-recursion-detection": "^3.972.8",
-        "@aws-sdk/middleware-user-agent": "^3.972.21",
+        "@aws-sdk/middleware-user-agent": "^3.972.22",
         "@aws-sdk/region-config-resolver": "^3.972.8",
         "@aws-sdk/types": "^3.973.6",
         "@aws-sdk/util-endpoints": "^3.996.5",
         "@aws-sdk/util-user-agent-browser": "^3.972.8",
-        "@aws-sdk/util-user-agent-node": "^3.973.7",
+        "@aws-sdk/util-user-agent-node": "^3.973.8",
         "@smithy/config-resolver": "^4.4.11",
-        "@smithy/core": "^3.23.11",
+        "@smithy/core": "^3.23.12",
         "@smithy/fetch-http-handler": "^5.3.15",
         "@smithy/hash-node": "^4.2.12",
         "@smithy/invalid-dependency": "^4.2.12",
         "@smithy/middleware-content-length": "^4.2.12",
-        "@smithy/middleware-endpoint": "^4.4.25",
-        "@smithy/middleware-retry": "^4.4.42",
-        "@smithy/middleware-serde": "^4.2.14",
+        "@smithy/middleware-endpoint": "^4.4.26",
+        "@smithy/middleware-retry": "^4.4.43",
+        "@smithy/middleware-serde": "^4.2.15",
         "@smithy/middleware-stack": "^4.2.12",
         "@smithy/node-config-provider": "^4.3.12",
-        "@smithy/node-http-handler": "^4.4.16",
+        "@smithy/node-http-handler": "^4.5.0",
         "@smithy/protocol-http": "^5.3.12",
-        "@smithy/smithy-client": "^4.12.5",
+        "@smithy/smithy-client": "^4.12.6",
         "@smithy/types": "^4.13.1",
         "@smithy/url-parser": "^4.2.12",
         "@smithy/util-base64": "^4.3.2",
         "@smithy/util-body-length-browser": "^4.2.2",
         "@smithy/util-body-length-node": "^4.2.3",
-        "@smithy/util-defaults-mode-browser": "^4.3.41",
-        "@smithy/util-defaults-mode-node": "^4.2.44",
+        "@smithy/util-defaults-mode-browser": "^4.3.42",
+        "@smithy/util-defaults-mode-node": "^4.2.45",
         "@smithy/util-endpoints": "^3.3.3",
         "@smithy/util-middleware": "^4.2.12",
         "@smithy/util-retry": "^4.2.12",
@@ -7920,12 +7920,12 @@
       }
     },
     "node_modules/@aws-sdk/credential-provider-login/node_modules/@aws-sdk/util-user-agent-node": {
-      "version": "3.973.7",
-      "resolved": "https://registry.npmjs.org/@aws-sdk/util-user-agent-node/-/util-user-agent-node-3.973.7.tgz",
-      "integrity": "sha512-Hz6EZMUAEzqUd7e+vZ9LE7mn+5gMbxltXy18v+YSFY+9LBJz15wkNZvw5JqfX3z0FS9n3bgUtz3L5rAsfh4YlA==",
+      "version": "3.973.8",
+      "resolved": "https://registry.npmjs.org/@aws-sdk/util-user-agent-node/-/util-user-agent-node-3.973.8.tgz",
+      "integrity": "sha512-Kvb96TafGPLYo4Z2GRCzQTne77epXgiZEo0DDXwavzkWmgDV/1XD1tMA766gzRcHHFUraWsE+4T8DKtPTZUxgQ==",
       "license": "Apache-2.0",
       "dependencies": {
-        "@aws-sdk/middleware-user-agent": "^3.972.21",
+        "@aws-sdk/middleware-user-agent": "^3.972.22",
         "@aws-sdk/types": "^3.973.6",
         "@smithy/node-config-provider": "^4.3.12",
         "@smithy/types": "^4.13.1",
@@ -7945,13 +7945,13 @@
       }
     },
     "node_modules/@aws-sdk/credential-provider-login/node_modules/@aws-sdk/xml-builder": {
-      "version": "3.972.11",
-      "resolved": "https://registry.npmjs.org/@aws-sdk/xml-builder/-/xml-builder-3.972.11.tgz",
-      "integrity": "sha512-iitV/gZKQMvY9d7ovmyFnFuTHbBAtrmLnvaSb/3X8vOKyevwtpmEtyc8AdhVWZe0pI/1GsHxlEvQeOePFzy7KQ==",
+      "version": "3.972.13",
+      "resolved": "https://registry.npmjs.org/@aws-sdk/xml-builder/-/xml-builder-3.972.13.tgz",
+      "integrity": "sha512-I/+BMxM4WE/6xL0tyV7tAUDOAXmyw/va1oGr/eSly43HmLUcD1G+v96vEKAA8VoLcZ03ZQo/PWzjmN9zQErqPQ==",
       "license": "Apache-2.0",
       "dependencies": {
         "@smithy/types": "^4.13.1",
-        "fast-xml-parser": "5.4.1",
+        "fast-xml-parser": "5.5.6",
         "tslib": "^2.6.2"
       },
       "engines": {
@@ -12864,9 +12864,9 @@
       }
     },
     "node_modules/@smithy/core": {
-      "version": "3.23.11",
-      "resolved": "https://registry.npmjs.org/@smithy/core/-/core-3.23.11.tgz",
-      "integrity": "sha512-952rGf7hBRnhUIaeLp6q4MptKW8sPFe5VvkoZ5qIzFAtx6c/QZ/54FS3yootsyUSf9gJX/NBqEBNdNR7jMIlpQ==",
+      "version": "3.23.12",
+      "resolved": "https://registry.npmjs.org/@smithy/core/-/core-3.23.12.tgz",
+      "integrity": "sha512-o9VycsYNtgC+Dy3I0yrwCqv9CWicDnke0L7EVOrZtJpjb2t0EjaEofmMrYc0T1Kn3yk32zm6cspxF9u9Bj7e5w==",
       "license": "Apache-2.0",
       "dependencies": {
         "@smithy/protocol-http": "^5.3.12",
@@ -12875,7 +12875,7 @@
         "@smithy/util-base64": "^4.3.2",
         "@smithy/util-body-length-browser": "^4.2.2",
         "@smithy/util-middleware": "^4.2.12",
-        "@smithy/util-stream": "^4.5.19",
+        "@smithy/util-stream": "^4.5.20",
         "@smithy/util-utf8": "^4.2.2",
         "@smithy/uuid": "^1.1.2",
         "tslib": "^2.6.2"
@@ -13084,13 +13084,13 @@
       }
     },
     "node_modules/@smithy/middleware-endpoint": {
-      "version": "4.4.25",
-      "resolved": "https://registry.npmjs.org/@smithy/middleware-endpoint/-/middleware-endpoint-4.4.25.tgz",
-      "integrity": "sha512-dqjLwZs2eBxIUG6Qtw8/YZ4DvzHGIf0DA18wrgtfP6a50UIO7e2nY0FPdcbv5tVJKqWCCU5BmGMOUwT7Puan+A==",
+      "version": "4.4.26",
+      "resolved": "https://registry.npmjs.org/@smithy/middleware-endpoint/-/middleware-endpoint-4.4.26.tgz",
+      "integrity": "sha512-8Qfikvd2GVKSm8S6IbjfwFlRY9VlMrj0Dp4vTwAuhqbX7NhJKE5DQc2bnfJIcY0B+2YKMDBWfvexbSZeejDgeg==",
       "license": "Apache-2.0",
       "dependencies": {
-        "@smithy/core": "^3.23.11",
-        "@smithy/middleware-serde": "^4.2.14",
+        "@smithy/core": "^3.23.12",
+        "@smithy/middleware-serde": "^4.2.15",
         "@smithy/node-config-provider": "^4.3.12",
         "@smithy/shared-ini-file-loader": "^4.4.7",
         "@smithy/types": "^4.13.1",
@@ -13103,15 +13103,15 @@
       }
     },
     "node_modules/@smithy/middleware-retry": {
-      "version": "4.4.42",
-      "resolved": "https://registry.npmjs.org/@smithy/middleware-retry/-/middleware-retry-4.4.42.tgz",
-      "integrity": "sha512-vbwyqHRIpIZutNXZpLAozakzamcINaRCpEy1MYmK6xBeW3xN+TyPRA123GjXnuxZIjc9848MRRCugVMTXxC4Eg==",
+      "version": "4.4.43",
+      "resolved": "https://registry.npmjs.org/@smithy/middleware-retry/-/middleware-retry-4.4.43.tgz",
+      "integrity": "sha512-ZwsifBdyuNHrFGmbc7bAfP2b54+kt9J2rhFd18ilQGAB+GDiP4SrawqyExbB7v455QVR7Psyhb2kjULvBPIhvA==",
       "license": "Apache-2.0",
       "dependencies": {
         "@smithy/node-config-provider": "^4.3.12",
         "@smithy/protocol-http": "^5.3.12",
         "@smithy/service-error-classification": "^4.2.12",
-        "@smithy/smithy-client": "^4.12.5",
+        "@smithy/smithy-client": "^4.12.6",
         "@smithy/types": "^4.13.1",
         "@smithy/util-middleware": "^4.2.12",
         "@smithy/util-retry": "^4.2.12",
@@ -13123,12 +13123,12 @@
       }
     },
     "node_modules/@smithy/middleware-serde": {
-      "version": "4.2.14",
-      "resolved": "https://registry.npmjs.org/@smithy/middleware-serde/-/middleware-serde-4.2.14.tgz",
-      "integrity": "sha512-+CcaLoLa5apzSRtloOyG7lQvkUw2ZDml3hRh4QiG9WyEPfW5Ke/3tPOPiPjUneuT59Tpn8+c3RVaUvvkkwqZwg==",
+      "version": "4.2.15",
+      "resolved": "https://registry.npmjs.org/@smithy/middleware-serde/-/middleware-serde-4.2.15.tgz",
+      "integrity": "sha512-ExYhcltZSli0pgAKOpQQe1DLFBLryeZ22605y/YS+mQpdNWekum9Ujb/jMKfJKgjtz1AZldtwA/wCYuKJgjjlg==",
       "license": "Apache-2.0",
       "dependencies": {
-        "@smithy/core": "^3.23.11",
+        "@smithy/core": "^3.23.12",
         "@smithy/protocol-http": "^5.3.12",
         "@smithy/types": "^4.13.1",
         "tslib": "^2.6.2"
@@ -13166,9 +13166,9 @@
       }
     },
     "node_modules/@smithy/node-http-handler": {
-      "version": "4.4.16",
-      "resolved": "https://registry.npmjs.org/@smithy/node-http-handler/-/node-http-handler-4.4.16.tgz",
-      "integrity": "sha512-ULC8UCS/HivdCB3jhi+kLFYe4B5gxH2gi9vHBfEIiRrT2jfKiZNiETJSlzRtE6B26XbBHjPtc8iZKSNqMol9bw==",
+      "version": "4.5.0",
+      "resolved": "https://registry.npmjs.org/@smithy/node-http-handler/-/node-http-handler-4.5.0.tgz",
+      "integrity": "sha512-Rnq9vQWiR1+/I6NZZMNzJHV6pZYyEHt2ZnuV3MG8z2NNenC4i/8Kzttz7CjZiHSmsN5frhXhg17z3Zqjjhmz1A==",
       "license": "Apache-2.0",
       "dependencies": {
         "@smithy/abort-controller": "^4.2.12",
@@ -13279,17 +13279,17 @@
       }
     },
     "node_modules/@smithy/smithy-client": {
-      "version": "4.12.5",
-      "resolved": "https://registry.npmjs.org/@smithy/smithy-client/-/smithy-client-4.12.5.tgz",
-      "integrity": "sha512-UqwYawyqSr/aog8mnLnfbPurS0gi4G7IYDcD28cUIBhsvWs1+rQcL2IwkUQ+QZ7dibaoRzhNF99fAQ9AUcO00w==",
+      "version": "4.12.6",
+      "resolved": "https://registry.npmjs.org/@smithy/smithy-client/-/smithy-client-4.12.6.tgz",
+      "integrity": "sha512-aib3f0jiMsJ6+cvDnXipBsGDL7ztknYSVqJs1FdN9P+u9tr/VzOR7iygSh6EUOdaBeMCMSh3N0VdyYsG4o91DQ==",
       "license": "Apache-2.0",
       "dependencies": {
-        "@smithy/core": "^3.23.11",
-        "@smithy/middleware-endpoint": "^4.4.25",
+        "@smithy/core": "^3.23.12",
+        "@smithy/middleware-endpoint": "^4.4.26",
         "@smithy/middleware-stack": "^4.2.12",
         "@smithy/protocol-http": "^5.3.12",
         "@smithy/types": "^4.13.1",
-        "@smithy/util-stream": "^4.5.19",
+        "@smithy/util-stream": "^4.5.20",
         "tslib": "^2.6.2"
       },
       "engines": {
@@ -13386,13 +13386,13 @@
       }
     },
     "node_modules/@smithy/util-defaults-mode-browser": {
-      "version": "4.3.41",
-      "resolved": "https://registry.npmjs.org/@smithy/util-defaults-mode-browser/-/util-defaults-mode-browser-4.3.41.tgz",
-      "integrity": "sha512-M1w1Ux0rSVvBOxIIiqbxvZvhnjQ+VUjJrugtORE90BbadSTH+jsQL279KRL3Hv0w69rE7EuYkV/4Lepz/NBW9g==",
+      "version": "4.3.42",
+      "resolved": "https://registry.npmjs.org/@smithy/util-defaults-mode-browser/-/util-defaults-mode-browser-4.3.42.tgz",
+      "integrity": "sha512-0vjwmcvkWAUtikXnWIUOyV6IFHTEeQUYh3JUZcDgcszF+hD/StAsQ3rCZNZEPHgI9kVNcbnyc8P2CBHnwgmcwg==",
       "license": "Apache-2.0",
       "dependencies": {
         "@smithy/property-provider": "^4.2.12",
-        "@smithy/smithy-client": "^4.12.5",
+        "@smithy/smithy-client": "^4.12.6",
         "@smithy/types": "^4.13.1",
         "tslib": "^2.6.2"
       },
@@ -13401,16 +13401,16 @@
       }
     },
     "node_modules/@smithy/util-defaults-mode-node": {
-      "version": "4.2.44",
-      "resolved": "https://registry.npmjs.org/@smithy/util-defaults-mode-node/-/util-defaults-mode-node-4.2.44.tgz",
-      "integrity": "sha512-YPze3/lD1KmWuZsl9JlfhcgGLX7AXhSoaCDtiPntUjNW5/YY0lOHjkcgxyE9x/h5vvS1fzDifMGjzqnNlNiqOQ==",
+      "version": "4.2.45",
+      "resolved": "https://registry.npmjs.org/@smithy/util-defaults-mode-node/-/util-defaults-mode-node-4.2.45.tgz",
+      "integrity": "sha512-q5dOqqfTgUcLe38TAGiFn9srToKj2YCHJ34QGOLzM+xYLLA+qRZv7N+33kl1MERVusue36ZHnlNaNEvY/PzSrw==",
       "license": "Apache-2.0",
       "dependencies": {
         "@smithy/config-resolver": "^4.4.11",
         "@smithy/credential-provider-imds": "^4.2.12",
         "@smithy/node-config-provider": "^4.3.12",
         "@smithy/property-provider": "^4.2.12",
-        "@smithy/smithy-client": "^4.12.5",
+        "@smithy/smithy-client": "^4.12.6",
         "@smithy/types": "^4.13.1",
         "tslib": "^2.6.2"
       },
@@ -13472,13 +13472,13 @@
       }
     },
     "node_modules/@smithy/util-stream": {
-      "version": "4.5.19",
-      "resolved": "https://registry.npmjs.org/@smithy/util-stream/-/util-stream-4.5.19.tgz",
-      "integrity": "sha512-v4sa+3xTweL1CLO2UP0p7tvIMH/Rq1X4KKOxd568mpe6LSLMQCnDHs4uv7m3ukpl3HvcN2JH6jiCS0SNRXKP/w==",
+      "version": "4.5.20",
+      "resolved": "https://registry.npmjs.org/@smithy/util-stream/-/util-stream-4.5.20.tgz",
+      "integrity": "sha512-4yXLm5n/B5SRBR2p8cZ90Sbv4zL4NKsgxdzCzp/83cXw2KxLEumt5p+GAVyRNZgQOSrzXn9ARpO0lUe8XSlSDw==",
       "license": "Apache-2.0",
       "dependencies": {
         "@smithy/fetch-http-handler": "^5.3.15",
-        "@smithy/node-http-handler": "^4.4.16",
+        "@smithy/node-http-handler": "^4.5.0",
         "@smithy/types": "^4.13.1",
         "@smithy/util-base64": "^4.3.2",
         "@smithy/util-buffer-from": "^4.2.2",
diff --git a/packages/types/src/index.ts b/packages/types/src/index.ts
index d7338053a..98cc0e126 100644
--- a/packages/types/src/index.ts
+++ b/packages/types/src/index.ts
@@ -105,6 +105,11 @@ export type {
   PatchV1RoutingConfigurationByRoutingConfigIdSubmitErrors,
   PatchV1RoutingConfigurationByRoutingConfigIdSubmitResponse,
   PatchV1RoutingConfigurationByRoutingConfigIdSubmitResponses,
+  PatchV1TemplateByTemplateIdApproveData,
+  PatchV1TemplateByTemplateIdApproveError,
+  PatchV1TemplateByTemplateIdApproveErrors,
+  PatchV1TemplateByTemplateIdApproveResponse,
+  PatchV1TemplateByTemplateIdApproveResponses,
   PatchV1TemplateByTemplateIdData,
   PatchV1TemplateByTemplateIdError,
   PatchV1TemplateByTemplateIdErrors,
diff --git a/packages/types/src/types.gen.ts b/packages/types/src/types.gen.ts
index 867459efc..e3c4df9e9 100644
--- a/packages/types/src/types.gen.ts
+++ b/packages/types/src/types.gen.ts
@@ -958,6 +958,44 @@ export type PutV1TemplateByTemplateIdResponses = {
 export type PutV1TemplateByTemplateIdResponse =
   PutV1TemplateByTemplateIdResponses[keyof PutV1TemplateByTemplateIdResponses];
 
+export type PatchV1TemplateByTemplateIdApproveData = {
+  body?: never;
+  headers: {
+    /**
+     * Lock number of the current version of the template
+     */
+    'X-Lock-Number': number;
+  };
+  path: {
+    /**
+     * ID of template to approve
+     */
+    templateId: string;
+  };
+  query?: never;
+  url: '/v1/template/{templateId}/approve';
+};
+
+export type PatchV1TemplateByTemplateIdApproveErrors = {
+  /**
+   * Error
+   */
+  default: Failure;
+};
+
+export type PatchV1TemplateByTemplateIdApproveError =
+  PatchV1TemplateByTemplateIdApproveErrors[keyof PatchV1TemplateByTemplateIdApproveErrors];
+
+export type PatchV1TemplateByTemplateIdApproveResponses = {
+  /**
+   * 200 response
+   */
+  200: TemplateSuccess;
+};
+
+export type PatchV1TemplateByTemplateIdApproveResponse =
+  PatchV1TemplateByTemplateIdApproveResponses[keyof PatchV1TemplateByTemplateIdApproveResponses];
+
 export type PostV1TemplateByTemplateIdGenerateLetterProofData = {
   /**
    * Template to update
diff --git a/tests/test-team/.context/test-context.json b/tests/test-team/.context/test-context.json
deleted file mode 100644
index 0967ef424..000000000
--- a/tests/test-team/.context/test-context.json
+++ /dev/null
@@ -1 +0,0 @@
-{}
diff --git a/tests/test-team/pages/letter/index.ts b/tests/test-team/pages/letter/index.ts
index 21c8ab5f1..802caab2e 100644
--- a/tests/test-team/pages/letter/index.ts
+++ b/tests/test-team/pages/letter/index.ts
@@ -3,6 +3,7 @@ export * from './template-mgmt-edit-template-campaign-page';
 export * from './template-mgmt-edit-template-name-page';
 export * from './template-mgmt-preview-letter-page';
 export * from './template-mgmt-preview-submitted-letter-page';
+export * from './template-mgmt-review-and-approve-letter-template-page';
 export * from './template-mgmt-submit-letter-page';
 export * from './template-mgmt-template-submitted-letter-page';
 export * from './template-mgmt-upload-bsl-letter-template-page';
diff --git a/tests/test-team/pages/letter/template-mgmt-preview-letter-page.ts b/tests/test-team/pages/letter/template-mgmt-preview-letter-page.ts
index 0fb6f1e35..d87acd841 100644
--- a/tests/test-team/pages/letter/template-mgmt-preview-letter-page.ts
+++ b/tests/test-team/pages/letter/template-mgmt-preview-letter-page.ts
@@ -104,6 +104,13 @@ export class TemplateMgmtPreviewLetterPage extends TemplateMgmtPreviewBasePage {
     await this.continueButton.click();
   }
 
+  summaryRowValue(label: string): Locator {
+    return this.page
+      .locator('.nhsuk-summary-list__row')
+      .filter({ hasText: label })
+      .locator('.nhsuk-summary-list__value');
+  }
+
   static getTemplateId(url: string) {
     const matches = url.match(TemplateMgmtPreviewLetterPage.urlRegexp);
 
diff --git a/tests/test-team/pages/letter/template-mgmt-review-and-approve-letter-template-page.ts b/tests/test-team/pages/letter/template-mgmt-review-and-approve-letter-template-page.ts
new file mode 100644
index 000000000..8b7b304c0
--- /dev/null
+++ b/tests/test-team/pages/letter/template-mgmt-review-and-approve-letter-template-page.ts
@@ -0,0 +1,23 @@
+import { Locator, Page } from '@playwright/test';
+import { TemplateMgmtBasePage } from '../template-mgmt-base-page';
+
+export class TemplateMgmtReviewAndApproveLetterTemplatePage extends TemplateMgmtBasePage {
+  static readonly pathTemplate =
+    '/review-and-approve-letter-template/:templateId';
+
+  public static readonly urlRegexp = new RegExp(
+    /\/templates\/review-and-approve-letter-template\/([\dA-Fa-f-]+)$/
+  );
+
+  readonly approveButton: Locator;
+
+  constructor(page: Page) {
+    super(page);
+
+    this.approveButton = page.getByRole('button', { name: 'Approve' });
+  }
+
+  async clickApproveButton() {
+    await this.approveButton.click();
+  }
+}
diff --git a/tests/test-team/template-mgmt-accessibility/letter-templates.accessibility.spec.ts b/tests/test-team/template-mgmt-accessibility/letter-templates.accessibility.spec.ts
index 3a0cfc010..458c36d53 100644
--- a/tests/test-team/template-mgmt-accessibility/letter-templates.accessibility.spec.ts
+++ b/tests/test-team/template-mgmt-accessibility/letter-templates.accessibility.spec.ts
@@ -9,6 +9,7 @@ import {
   TemplateMgmtEditTemplateNamePage,
   TemplateMgmtPreviewLetterPage,
   TemplateMgmtPreviewSubmittedLetterPage,
+  TemplateMgmtReviewAndApproveLetterTemplatePage,
   TemplateMgmtSubmitLetterPage,
   TemplateMgmtTemplateSubmittedLetterPage,
   TemplateMgmtUploadBSLLetterTemplatePage,
@@ -27,6 +28,7 @@ const templateIds = {
   AUTHORING: randomUUID(),
   AUTHORING_INITIAL_SPINNER: randomUUID(),
   AUTHORING_MISSING_ADDRESS: randomUUID(),
+  AUTHORING_WITH_RENDERS: randomUUID(),
   LETTER: randomUUID(),
   LETTER_ERROR: randomUUID(),
   LETTER_SUBMITTED: randomUUID(),
@@ -48,12 +50,27 @@ test.beforeAll(async () => {
     testUsers.UserWithMultipleCampaigns.userId
   );
 
+  const [globalLetterVariant] =
+    await context.letterVariants.getGlobalLetterVariants();
+
   const authoring = TemplateFactory.createAuthoringLetterTemplate(
     templateIds.AUTHORING,
     authoringEnabledWithMultipleCampaignsUser,
     `Authoring letter template - ${templateIds.AUTHORING}`
   );
 
+  const authoringWithRenders = TemplateFactory.createAuthoringLetterTemplate(
+    templateIds.AUTHORING_WITH_RENDERS,
+    authoringEnabledWithMultipleCampaignsUser,
+    `Authoring letter template - ${templateIds.AUTHORING}`,
+    'NOT_YET_SUBMITTED',
+    {
+      longFormRender: { status: 'RENDERED' },
+      shortFormRender: { status: 'RENDERED' },
+      letterVariantId: globalLetterVariant.id,
+    }
+  );
+
   const authoringMissingAddress = TemplateFactory.createAuthoringLetterTemplate(
     templateIds.AUTHORING_MISSING_ADDRESS,
     authoringEnabledWithMultipleCampaignsUser,
@@ -100,6 +117,7 @@ test.beforeAll(async () => {
   await templateStorageHelper.seedTemplateData([
     authoring,
     authoringMissingAddress,
+    authoringWithRenders,
     letter,
     letterWithError,
     letterSubmitted,
@@ -345,5 +363,12 @@ test.describe('Letter templates', () => {
           },
         }
       ));
+
+    test('Review and approve letter template page', async ({ page, analyze }) =>
+      analyze(
+        new TemplateMgmtReviewAndApproveLetterTemplatePage(page)
+          .setPathParam('templateId', templateIds.AUTHORING_WITH_RENDERS)
+          .setSearchParam('lockNumber', '0')
+      ));
   });
 });
diff --git a/tests/test-team/template-mgmt-accessibility/route-coverage.accessibility.spec.ts b/tests/test-team/template-mgmt-accessibility/route-coverage.accessibility.spec.ts
index d5e271562..3e311aa1f 100644
--- a/tests/test-team/template-mgmt-accessibility/route-coverage.accessibility.spec.ts
+++ b/tests/test-team/template-mgmt-accessibility/route-coverage.accessibility.spec.ts
@@ -50,6 +50,7 @@ import {
   TemplateMgmtEditTemplateNamePage,
   TemplateMgmtPreviewLetterPage,
   TemplateMgmtPreviewSubmittedLetterPage,
+  TemplateMgmtReviewAndApproveLetterTemplatePage,
   TemplateMgmtSubmitLetterPage,
   TemplateMgmtTemplateSubmittedLetterPage,
   TemplateMgmtUploadBSLLetterTemplatePage,
@@ -130,19 +131,20 @@ const allPages: (typeof TemplateMgmtBasePage)[] = [
 
   // Letter
   TemplateMgmtChoosePrintingAndPostagePage,
-  TemplateMgmtUploadLetterPage,
-  TemplateMgmtUploadStandardEnglishLetterTemplatePage,
-  TemplateMgmtUploadLargePrintLetterTemplatePage,
-  TemplateMgmtUploadBSLLetterTemplatePage,
-  TemplateMgmtUploadOtherLanguageLetterTemplatePage,
-  TemplateMgmtUploadLetterMissingCampaignClientIdPage,
-  TemplateMgmtEditTemplateNamePage,
   TemplateMgmtEditTemplateCampaignPage,
+  TemplateMgmtEditTemplateNamePage,
   TemplateMgmtPreviewLetterPage,
   TemplateMgmtPreviewSubmittedLetterPage,
+  TemplateMgmtRequestProofPage,
+  TemplateMgmtReviewAndApproveLetterTemplatePage,
   TemplateMgmtSubmitLetterPage,
   TemplateMgmtTemplateSubmittedLetterPage,
-  TemplateMgmtRequestProofPage,
+  TemplateMgmtUploadBSLLetterTemplatePage,
+  TemplateMgmtUploadLargePrintLetterTemplatePage,
+  TemplateMgmtUploadLetterMissingCampaignClientIdPage,
+  TemplateMgmtUploadLetterPage,
+  TemplateMgmtUploadOtherLanguageLetterTemplatePage,
+  TemplateMgmtUploadStandardEnglishLetterTemplatePage,
 
   // Routing / Message plans
   RoutingMessagePlansPage,
diff --git a/tests/test-team/template-mgmt-api-tests/approve-template.api.spec.ts b/tests/test-team/template-mgmt-api-tests/approve-template.api.spec.ts
new file mode 100644
index 000000000..225240b10
--- /dev/null
+++ b/tests/test-team/template-mgmt-api-tests/approve-template.api.spec.ts
@@ -0,0 +1,723 @@
+import { test, expect } from '@playwright/test';
+import { type TestUser, testUsers } from '../helpers/auth/cognito-auth-helper';
+import { TemplateStorageHelper } from '../helpers/db/template-storage-helper';
+import {
+  isoDateRegExp,
+  uuidRegExp,
+} from 'nhs-notify-web-template-management-test-helper-utils';
+import { randomUUID } from 'node:crypto';
+import { TemplateFactory } from '../helpers/factories/template-factory';
+import { getTestContext } from '../helpers/context/context';
+
+test.describe('PATCH /v1/template/:templateId/approve', () => {
+  const context = getTestContext();
+  const templateStorageHelper = new TemplateStorageHelper();
+  let userDifferentClient: TestUser;
+  let userLetterAuthoring: TestUser;
+  let userLetterAuthoringSharedClient: TestUser;
+
+  test.beforeAll(async () => {
+    userLetterAuthoring = await context.auth.getTestUser(
+      testUsers.UserLetterAuthoringEnabled.userId
+    );
+    userDifferentClient = await context.auth.getTestUser(
+      testUsers.User2.userId
+    );
+    userLetterAuthoringSharedClient = await context.auth.getTestUser(
+      testUsers.UserLetterAuthoringEnabledSharedClient.userId
+    );
+  });
+
+  test.afterAll(async () => {
+    await templateStorageHelper.deleteAdHocTemplates();
+    await templateStorageHelper.deleteSeededTemplates();
+  });
+
+  test('returns 401 if no auth token', async ({ request }) => {
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/some-template/approve`,
+      {
+        headers: {
+          'X-Lock-Number': '0',
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(401);
+
+    expect(await response.json()).toEqual({
+      message: 'Unauthorized',
+    });
+  });
+
+  test('returns 404 if template does not exist', async ({ request }) => {
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/noexist/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': '0',
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(404);
+
+    expect(data).toEqual({
+      statusCode: 404,
+      technicalMessage: 'Template not found',
+    });
+  });
+
+  test('returns 404 if template exists but is owned by a different client', async ({
+    request,
+  }) => {
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'other client owned'
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { id: templateId, lockNumber } = letterTemplate;
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${templateId}/approve`,
+      {
+        headers: {
+          Authorization: await userDifferentClient.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const data = await response.json();
+
+    expect(response.status(), JSON.stringify(data)).toBe(404);
+
+    expect(data).toEqual({
+      statusCode: 404,
+      technicalMessage: 'Template not found',
+    });
+  });
+
+  test('returns 400 if the lock number header is not set', async ({
+    request,
+  }) => {
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'no locknumber'
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { id: templateId } = letterTemplate;
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${templateId}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(400);
+
+    expect(data).toEqual({
+      statusCode: 400,
+      technicalMessage: 'Invalid lock number provided',
+    });
+  });
+
+  test('returns 409 if the lock number does not match', async ({ request }) => {
+    const [letterVariant] =
+      await context.letterVariants.getGlobalLetterVariants();
+
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'lock mismatch',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: letterVariant.id,
+        longFormRender: { status: 'RENDERED' },
+        shortFormRender: { status: 'RENDERED' },
+      }
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { id: templateId, lockNumber } = letterTemplate;
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${templateId}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(lockNumber + 1),
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(409);
+
+    expect(data).toEqual({
+      statusCode: 409,
+      technicalMessage:
+        'Lock number mismatch - Template has been modified since last read',
+    });
+  });
+
+  test('returns 200 and sets status to PROOF_APPROVED', async ({ request }) => {
+    const [letterVariant] =
+      await context.letterVariants.getGlobalLetterVariants();
+
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'success',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: letterVariant.id,
+        longFormRender: { status: 'RENDERED' },
+        shortFormRender: { status: 'RENDERED' },
+      }
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { id: templateId, lockNumber, createdAt, name } = letterTemplate;
+
+    const start = new Date();
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${templateId}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const result = await response.json();
+    expect(response.status(), JSON.stringify(result, null, 2)).toBe(200);
+
+    expect(result).toEqual({
+      statusCode: 200,
+      data: expect.objectContaining({
+        createdAt: expect.stringMatching(isoDateRegExp),
+        id: expect.stringMatching(uuidRegExp),
+        name,
+        templateStatus: 'PROOF_APPROVED',
+        templateType: 'LETTER',
+        updatedAt: expect.stringMatching(isoDateRegExp),
+        lockNumber: lockNumber + 1,
+      }),
+    });
+
+    expect(result.data.updatedAt).toBeDateRoughlyBetween([start, new Date()]);
+    expect(result.data.createdAt).toEqual(createdAt);
+  });
+
+  test('user belonging to the same client as the creator can approve', async ({
+    request,
+  }) => {
+    const [letterVariant] =
+      await context.letterVariants.getGlobalLetterVariants();
+
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'success shared ownership',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: letterVariant.id,
+        longFormRender: { status: 'RENDERED' },
+        shortFormRender: { status: 'RENDERED' },
+      }
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { createdAt, lockNumber, id } = letterTemplate;
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoringSharedClient.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const result = await response.json();
+    expect(response.status(), JSON.stringify(result, null, 2)).toBe(200);
+
+    expect(userLetterAuthoring.clientId).toBe(
+      userLetterAuthoringSharedClient.clientId
+    );
+
+    expect(result).toEqual({
+      statusCode: 200,
+      data: expect.objectContaining({
+        clientId: userLetterAuthoring.clientId,
+        createdAt,
+        id,
+        templateStatus: 'PROOF_APPROVED',
+        updatedAt: expect.stringMatching(isoDateRegExp),
+        lockNumber: lockNumber + 1,
+        updatedBy: `INTERNAL_USER#${userLetterAuthoringSharedClient.internalUserId}`,
+      }),
+    });
+  });
+
+  test('returns 400 - cannot approve an already approved template', async ({
+    request,
+  }) => {
+    const [letterVariant] =
+      await context.letterVariants.getGlobalLetterVariants();
+
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'already approved',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: letterVariant.id,
+        longFormRender: { status: 'RENDERED' },
+        shortFormRender: { status: 'RENDERED' },
+      }
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { lockNumber, id } = letterTemplate;
+
+    const approveResponse = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const approveResult = await approveResponse.json();
+
+    expect(
+      approveResponse.status(),
+      JSON.stringify(approveResult, null, 2)
+    ).toBe(200);
+
+    const failedResponse = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(approveResult.data.lockNumber),
+        },
+      }
+    );
+
+    const failedResult = await failedResponse.json();
+
+    expect(failedResponse.status(), JSON.stringify(failedResult)).toBe(400);
+    expect(failedResult).toEqual({
+      statusCode: 400,
+      technicalMessage: 'Template cannot be approved',
+    });
+  });
+
+  test('returns 400 - cannot approve a non-letter template', async ({
+    request,
+  }) => {
+    const appTemplate = TemplateFactory.createNhsAppTemplate(
+      randomUUID(),
+      userLetterAuthoring
+    );
+
+    await templateStorageHelper.seedTemplateData([appTemplate]);
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${appTemplate.id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(appTemplate.lockNumber),
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(400);
+
+    expect(data).toEqual({
+      statusCode: 400,
+      technicalMessage: 'Template cannot be approved',
+    });
+  });
+
+  test('returns 400 - cannot approve a PDF letter template', async ({
+    request,
+  }) => {
+    const pdfLetterTemplate = TemplateFactory.uploadLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'Test PDF Letter template'
+    );
+
+    await templateStorageHelper.seedTemplateData([pdfLetterTemplate]);
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${pdfLetterTemplate.id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(pdfLetterTemplate.lockNumber),
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(400);
+
+    expect(data).toEqual({
+      statusCode: 400,
+      technicalMessage: 'Template cannot be approved',
+    });
+  });
+
+  test('returns 404 - cannot approve a deleted template', async ({
+    request,
+  }) => {
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'deleted',
+      'DELETED'
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { lockNumber, id } = letterTemplate;
+
+    const approveResponse = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const data = await approveResponse.json();
+    expect(approveResponse.status(), JSON.stringify(data)).toBe(404);
+
+    expect(data).toEqual({
+      statusCode: 404,
+      technicalMessage: 'Template not found',
+    });
+  });
+
+  test('returns 400 - cannot approve template without campaignId', async ({
+    request,
+  }) => {
+    const [letterVariant] =
+      await context.letterVariants.getGlobalLetterVariants();
+
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'no campaign',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: letterVariant.id,
+        campaignId: null,
+        shortFormRender: { status: 'RENDERED' },
+        longFormRender: { status: 'RENDERED' },
+      }
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { id, lockNumber } = letterTemplate;
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(400);
+
+    expect(data).toEqual({
+      statusCode: 400,
+      technicalMessage: 'Template cannot be approved',
+    });
+  });
+
+  test('returns 400 - cannot approve template without letterVariantId', async ({
+    request,
+  }) => {
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'no letter variant ID',
+      'NOT_YET_SUBMITTED',
+      {
+        shortFormRender: { status: 'RENDERED' },
+        longFormRender: { status: 'RENDERED' },
+      }
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { id, lockNumber } = letterTemplate;
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(400);
+
+    expect(data).toEqual({
+      statusCode: 400,
+      technicalMessage: 'Template cannot be approved',
+    });
+  });
+
+  test('returns 404 - cannot approve template where letterVariantId refers to a non-existant variant', async ({
+    request,
+  }) => {
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'letter variant does not exist',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: 'notavariant',
+        shortFormRender: { status: 'RENDERED' },
+        longFormRender: { status: 'RENDERED' },
+      }
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { id, lockNumber } = letterTemplate;
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(404);
+
+    expect(data).toEqual({
+      statusCode: 404,
+      technicalMessage: 'Letter variant not found',
+    });
+  });
+
+  test('returns 400 - cannot approve when shortFormRender is missing', async ({
+    request,
+  }) => {
+    const [letterVariant] =
+      await context.letterVariants.getGlobalLetterVariants();
+
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'no short render',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: letterVariant.id,
+        shortFormRender: false,
+        longFormRender: { status: 'RENDERED' },
+      }
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { id, lockNumber } = letterTemplate;
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(400);
+
+    expect(data).toEqual({
+      statusCode: 400,
+      technicalMessage:
+        'One or more personalised rendered example has not been generated',
+    });
+  });
+
+  test('returns 400 - cannot approve when longFormRender is missing', async ({
+    request,
+  }) => {
+    const [letterVariant] =
+      await context.letterVariants.getGlobalLetterVariants();
+
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'no long render',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: letterVariant.id,
+        shortFormRender: { status: 'RENDERED' },
+        longFormRender: false,
+      }
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { id, lockNumber } = letterTemplate;
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(400);
+
+    expect(data).toEqual({
+      statusCode: 400,
+      technicalMessage:
+        'One or more personalised rendered example has not been generated',
+    });
+  });
+
+  test('returns 400 - cannot approve when renders are not yet complete', async ({
+    request,
+  }) => {
+    const [letterVariant] =
+      await context.letterVariants.getGlobalLetterVariants();
+
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'pending renders',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: letterVariant.id,
+        shortFormRender: { status: 'PENDING' },
+        longFormRender: { status: 'PENDING' },
+      }
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { id, lockNumber } = letterTemplate;
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(400);
+
+    expect(data).toEqual({
+      statusCode: 400,
+      technicalMessage:
+        'One or more personalised rendered example has not been generated',
+    });
+  });
+
+  test('returns 400 - page count exceeds max sheets allowed by letter variant', async ({
+    request,
+  }) => {
+    const globalVariants =
+      await context.letterVariants.getGlobalLetterVariants();
+
+    const letterVariant = globalVariants.find(
+      (v) => v.maxSheets === 5 && v.bothSides
+    );
+
+    expect(letterVariant).toBeDefined();
+
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userLetterAuthoring,
+      'renders too long',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: letterVariant!.id,
+        shortFormRender: { status: 'RENDERED', pageCount: 11 },
+        longFormRender: { status: 'RENDERED', pageCount: 11 },
+      }
+    );
+
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const { id, lockNumber } = letterTemplate;
+
+    const response = await request.patch(
+      `${process.env.API_BASE_URL}/v1/template/${id}/approve`,
+      {
+        headers: {
+          Authorization: await userLetterAuthoring.getAccessToken(),
+          'X-Lock-Number': String(lockNumber),
+        },
+      }
+    );
+
+    const data = await response.json();
+    expect(response.status(), JSON.stringify(data)).toBe(400);
+
+    expect(data).toEqual({
+      statusCode: 400,
+      technicalMessage:
+        'Letter template exceeded maximum number of sheets allowed by letter variant',
+    });
+  });
+});
diff --git a/tests/test-team/template-mgmt-api-tests/delete-template.api.spec.ts b/tests/test-team/template-mgmt-api-tests/delete-template.api.spec.ts
index 2e76a419a..12bddbcb8 100644
--- a/tests/test-team/template-mgmt-api-tests/delete-template.api.spec.ts
+++ b/tests/test-team/template-mgmt-api-tests/delete-template.api.spec.ts
@@ -138,7 +138,7 @@ test.describe('DELETE /v1/template/:templateId', () => {
       expect(deleteResponse.status()).toBe(204);
     });
 
-    test('returns 204 - can delete a proof approved letter', async ({
+    test('returns 204 - can delete a proof approved PDF letter', async ({
       request,
     }) => {
       const { id: templateId, lockNumber } = await createLetterTemplate(user1);
@@ -173,6 +173,39 @@ test.describe('DELETE /v1/template/:templateId', () => {
       expect(deleteResponse.status()).toBe(204);
     });
 
+    test('returns 204 - can delete a proof approved AUTHORING letter', async ({
+      request,
+    }) => {
+      const [letterVariant] =
+        await context.letterVariants.getGlobalLetterVariants();
+
+      const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+        randomUUID(),
+        user1,
+        'delete-approved-authoring-letter',
+        'PROOF_APPROVED',
+        {
+          letterVariantId: letterVariant.id,
+          longFormRender: { status: 'RENDERED' },
+          shortFormRender: { status: 'RENDERED' },
+        }
+      );
+
+      await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+      const deleteResponse = await request.delete(
+        `${process.env.API_BASE_URL}/v1/template/${letterTemplate.id}`,
+        {
+          headers: {
+            Authorization: await user1.getAccessToken(),
+            'X-Lock-Number': String(letterTemplate.lockNumber),
+          },
+        }
+      );
+
+      expect(deleteResponse.status()).toBe(204);
+    });
+
     test('returns 400 - cannot delete a submitted template', async ({
       request,
     }) => {
diff --git a/tests/test-team/template-mgmt-api-tests/get-letter-variant.api.spec.ts b/tests/test-team/template-mgmt-api-tests/get-letter-variant.api.spec.ts
index cd849d348..218624b7b 100644
--- a/tests/test-team/template-mgmt-api-tests/get-letter-variant.api.spec.ts
+++ b/tests/test-team/template-mgmt-api-tests/get-letter-variant.api.spec.ts
@@ -39,7 +39,7 @@ test.describe('GET /v1/letter-variant/:id', () => {
     expect(response.status()).toBe(404);
     expect(await response.json()).toEqual({
       statusCode: 404,
-      technicalMessage: 'Letter Variant not found',
+      technicalMessage: 'Letter variant not found',
     });
   });
 
@@ -128,7 +128,7 @@ test.describe('GET /v1/letter-variant/:id', () => {
     expect(response.status()).toBe(404);
     expect(await response.json()).toEqual({
       statusCode: 404,
-      technicalMessage: 'Letter Variant not found',
+      technicalMessage: 'Letter variant not found',
     });
   });
 
@@ -154,7 +154,7 @@ test.describe('GET /v1/letter-variant/:id', () => {
     expect(response.status()).toBe(404);
     expect(await response.json()).toEqual({
       statusCode: 404,
-      technicalMessage: 'Letter Variant not found',
+      technicalMessage: 'Letter variant not found',
     });
   });
 });
diff --git a/tests/test-team/template-mgmt-component-tests/letter/template-mgmt-preview-letter-page.component.spec.ts b/tests/test-team/template-mgmt-component-tests/letter/template-mgmt-preview-letter-page.component.spec.ts
index a93a82c73..83818ab63 100644
--- a/tests/test-team/template-mgmt-component-tests/letter/template-mgmt-preview-letter-page.component.spec.ts
+++ b/tests/test-team/template-mgmt-component-tests/letter/template-mgmt-preview-letter-page.component.spec.ts
@@ -1,6 +1,7 @@
 import { test, expect } from '@playwright/test';
 import { TemplateStorageHelper } from '../../helpers/db/template-storage-helper';
 import { TemplateFactory } from '../../helpers/factories/template-factory';
+import { makeLetterVariant } from '../../helpers/factories/letter-variant-factory';
 import { Template } from '../../helpers/types';
 import {
   testUsers,
@@ -12,7 +13,33 @@ import { TemplateMgmtSubmitLetterPage } from '../../pages/letter/template-mgmt-s
 import { TemplateMgmtRequestProofPage } from '../../pages/template-mgmt-request-proof-page';
 import { loginAsUser } from '../../helpers/auth/login-as-user';
 
-async function createTemplates(user: TestUser) {
+async function createLetterVariants(clientId: string) {
+  const context = getTestContext();
+
+  const doubleSided = makeLetterVariant({
+    clientId,
+    bothSides: true,
+    name: 'Double-sided test variant',
+  });
+
+  const singleSided = makeLetterVariant({
+    clientId,
+    bothSides: false,
+    name: 'Single-sided test variant',
+  });
+
+  await Promise.all([
+    context.letterVariants.createLetterVariant(doubleSided),
+    context.letterVariants.createLetterVariant(singleSided),
+  ]);
+
+  return { doubleSided, singleSided };
+}
+
+function createTemplates(
+  user: TestUser,
+  variants: Awaited<ReturnType<typeof createLetterVariants>>
+) {
   const withProofsBase = TemplateFactory.uploadLetterTemplate(
     'C8814A1D-1F3A-4AE4-9FE3-BDDA76EADF0C',
     user,
@@ -124,7 +151,7 @@ async function createTemplates(user: TestUser) {
       'authoring-letter-valid',
       'NOT_YET_SUBMITTED',
       {
-        letterVariantId: 'variant-123',
+        letterVariantId: variants.doubleSided.id,
         initialRender: { pageCount: 4 },
       }
     ),
@@ -279,18 +306,29 @@ async function createTemplates(user: TestUser) {
           },
         }
       ),
+    authoringSingleSided: TemplateFactory.createAuthoringLetterTemplate(
+      'AABB1122-3344-5566-7788-99AABBCCDDEE',
+      user,
+      'authoring-single-sided',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: variants.singleSided.id,
+        initialRender: { pageCount: 4 },
+      }
+    ),
   };
 }
 
 test.describe('Preview Letter template Page', () => {
-  let templates: Awaited<ReturnType<typeof createTemplates>>;
+  let templates: ReturnType<typeof createTemplates>;
 
   const templateStorageHelper = new TemplateStorageHelper();
 
   test.beforeAll(async () => {
     const context = getTestContext();
     const user = await context.auth.getTestUser(testUsers.User1.userId);
-    templates = await createTemplates(user);
+    const variants = await createLetterVariants(user.clientId);
+    templates = createTemplates(user, variants);
     await templateStorageHelper.seedTemplateData(Object.values(templates));
   });
 
@@ -581,6 +619,12 @@ test.describe('Preview Letter template Page', () => {
       await expect(previewPage.editNameLink).toBeVisible();
 
       await expect(previewPage.statusTag).toBeVisible();
+
+      await expect(previewPage.summaryRowValue('Total pages')).toHaveText('4');
+      await expect(previewPage.summaryRowValue('Sheets')).toHaveText('2');
+
+      await expect(previewPage.sheetsAction).toBeVisible();
+      await expect(previewPage.statusAction).toBeVisible();
     });
 
     test('when initial render is recently requested (in PENDING status), the spinner is shown', async ({
@@ -1315,5 +1359,19 @@ test.describe('Preview Letter template Page', () => {
         await expect(previewPage.campaignAction).toHaveText(/Edit/);
       });
     });
+
+    test('calculates sheets as single-sided when bothSides is false', async ({
+      page,
+    }) => {
+      const previewPage = new TemplateMgmtPreviewLetterPage(page).setPathParam(
+        'templateId',
+        templates.authoringSingleSided.id
+      );
+
+      await previewPage.loadPage();
+
+      await expect(previewPage.summaryRowValue('Total pages')).toHaveText('4');
+      await expect(previewPage.summaryRowValue('Sheets')).toHaveText('4');
+    });
   });
 });
diff --git a/tests/test-team/template-mgmt-component-tests/letter/template-mgmt-review-and-approve-letter-template-page.component.spec.ts b/tests/test-team/template-mgmt-component-tests/letter/template-mgmt-review-and-approve-letter-template-page.component.spec.ts
new file mode 100644
index 000000000..f0baa753b
--- /dev/null
+++ b/tests/test-team/template-mgmt-component-tests/letter/template-mgmt-review-and-approve-letter-template-page.component.spec.ts
@@ -0,0 +1,210 @@
+import { test, expect } from '@playwright/test';
+import { TemplateStorageHelper } from '../../helpers/db/template-storage-helper';
+import { TemplateFactory } from '../../helpers/factories/template-factory';
+import { testUsers } from '../../helpers/auth/cognito-auth-helper';
+import { TemplateMgmtReviewAndApproveLetterTemplatePage } from '../../pages/letter/template-mgmt-review-and-approve-letter-template-page';
+import { getTestContext } from '../../helpers/context/context';
+
+async function createTemplates() {
+  const context = getTestContext();
+  const user = await context.auth.getTestUser(testUsers.User1.userId);
+
+  const [globalVariant] =
+    await context.letterVariants.getGlobalLetterVariants();
+
+  return {
+    valid: TemplateFactory.createAuthoringLetterTemplate(
+      '95e90d9d-4efa-4dd9-a35e-40d71e8e0abb',
+      user,
+      'review-approve-valid',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: globalVariant.id,
+        shortFormRender: { status: 'RENDERED' },
+        longFormRender: { status: 'RENDERED' },
+      }
+    ),
+
+    validForApproval: TemplateFactory.createAuthoringLetterTemplate(
+      '434bcde9-f1ae-4035-8cd8-80e4cb38756c',
+      user,
+      'review-approve-submit',
+      'NOT_YET_SUBMITTED',
+      {
+        letterVariantId: globalVariant.id,
+        shortFormRender: { status: 'RENDERED' },
+        longFormRender: { status: 'RENDERED' },
+      }
+    ),
+
+    withoutLetterVariantId: TemplateFactory.createAuthoringLetterTemplate(
+      '9cd300e8-4ba2-4d42-bbde-062b32ce3490',
+      user,
+      'review-approve-no-variant',
+      'NOT_YET_SUBMITTED',
+      {
+        shortFormRender: { status: 'RENDERED' },
+        longFormRender: { status: 'RENDERED' },
+      }
+    ),
+
+    nonLetterSms: {
+      ...TemplateFactory.createEmailTemplate(
+        '0a41e866-171b-42f4-887e-70b75db118ca',
+        user
+      ),
+      name: 'review-approve-non-letter',
+      subject: 'review-approve-non-letter',
+      message: 'review-approve-non-letter',
+    },
+
+    pdfLetter: TemplateFactory.uploadLetterTemplate(
+      '7e8a6ac4-8562-4e27-a0a8-5f2b06f60d0f',
+      user,
+      'review-approve-pdf-letter'
+    ),
+  };
+}
+
+test.describe('Review and Approve Letter Template Page', () => {
+  const templateStorageHelper = new TemplateStorageHelper();
+  let templates: Awaited<ReturnType<typeof createTemplates>>;
+
+  test.beforeAll(async () => {
+    templates = await createTemplates();
+    await templateStorageHelper.seedTemplateData(Object.values(templates));
+  });
+
+  test.afterAll(async () => {
+    await templateStorageHelper.deleteSeededTemplates();
+  });
+
+  test('when user visits page, then page is loaded with correct heading and approve button', async ({
+    page,
+  }) => {
+    const reviewPage = new TemplateMgmtReviewAndApproveLetterTemplatePage(page)
+      .setPathParam('templateId', templates.valid.id)
+      .setSearchParam('lockNumber', String(templates.valid.lockNumber));
+
+    await reviewPage.loadPage();
+
+    await expect(page).toHaveURL(reviewPage.getUrl());
+
+    await expect(reviewPage.pageHeading).toContainText(templates.valid.name);
+
+    await expect(reviewPage.approveButton).toBeVisible();
+
+    await expect(reviewPage.approveButton).toHaveText(
+      'Approve letter template'
+    );
+
+    await expect(page.getByTestId('sheets-action')).toBeHidden();
+    await expect(page.getByTestId('status-action')).toBeHidden();
+  });
+
+  test('when user clicks approve, then the template is approved and user is redirected', async ({
+    page,
+    baseURL,
+  }) => {
+    const reviewPage = new TemplateMgmtReviewAndApproveLetterTemplatePage(page)
+      .setPathParam('templateId', templates.validForApproval.id)
+      .setSearchParam(
+        'lockNumber',
+        String(templates.validForApproval.lockNumber)
+      );
+
+    await reviewPage.loadPage();
+
+    await expect(reviewPage.approveButton).toBeVisible();
+
+    await reviewPage.clickApproveButton();
+
+    await expect(page).toHaveURL(
+      `${baseURL}/templates/letter-template-approved/${templates.validForApproval.id}`
+    );
+  });
+
+  test('redirects to preview page when lockNumber query parameter is missing', async ({
+    page,
+  }) => {
+    const reviewPage = new TemplateMgmtReviewAndApproveLetterTemplatePage(
+      page
+    ).setPathParam('templateId', templates.valid.id);
+
+    await reviewPage.loadPage();
+
+    await expect(page).toHaveURL(
+      `/templates/preview-letter-template/${templates.valid.id}`
+    );
+  });
+
+  test('redirects to preview page when lockNumber query parameter is invalid', async ({
+    page,
+  }) => {
+    const reviewPage = new TemplateMgmtReviewAndApproveLetterTemplatePage(page)
+      .setPathParam('templateId', templates.valid.id)
+      .setSearchParam('lockNumber', 'invalid');
+
+    await reviewPage.loadPage();
+
+    await expect(page).toHaveURL(
+      `/templates/preview-letter-template/${templates.valid.id}`
+    );
+  });
+
+  test('redirects to preview page when template has no letterVariantId', async ({
+    page,
+  }) => {
+    const reviewPage = new TemplateMgmtReviewAndApproveLetterTemplatePage(page)
+      .setPathParam('templateId', templates.withoutLetterVariantId.id)
+      .setSearchParam(
+        'lockNumber',
+        String(templates.withoutLetterVariantId.lockNumber)
+      );
+
+    await reviewPage.loadPage();
+
+    await expect(page).toHaveURL(
+      `/templates/preview-letter-template/${templates.withoutLetterVariantId.id}`
+    );
+  });
+
+  test('redirects to invalid-template page when template is not a letter', async ({
+    page,
+    baseURL,
+  }) => {
+    const reviewPage = new TemplateMgmtReviewAndApproveLetterTemplatePage(page)
+      .setPathParam('templateId', templates.nonLetterSms.id)
+      .setSearchParam('lockNumber', String(templates.nonLetterSms.lockNumber));
+
+    await reviewPage.loadPage();
+
+    await expect(page).toHaveURL(`${baseURL}/templates/invalid-template`);
+  });
+
+  test('redirects to invalid-template page when letter has PDF letterVersion', async ({
+    page,
+    baseURL,
+  }) => {
+    const reviewPage = new TemplateMgmtReviewAndApproveLetterTemplatePage(page)
+      .setPathParam('templateId', templates.pdfLetter.id)
+      .setSearchParam('lockNumber', String(templates.pdfLetter.lockNumber));
+
+    await reviewPage.loadPage();
+
+    await expect(page).toHaveURL(`${baseURL}/templates/invalid-template`);
+  });
+
+  test('redirects to invalid-template page when template does not exist', async ({
+    page,
+    baseURL,
+  }) => {
+    const reviewPage = new TemplateMgmtReviewAndApproveLetterTemplatePage(
+      page
+    ).setPathParam('templateId', 'non-existent-template-id');
+
+    await reviewPage.loadPage();
+
+    await expect(page).toHaveURL(`${baseURL}/templates/invalid-template`);
+  });
+});
diff --git a/tests/test-team/template-mgmt-component-tests/template-protected-routes.component.spec.ts b/tests/test-team/template-mgmt-component-tests/template-protected-routes.component.spec.ts
index ae9ea709e..e34d18888 100644
--- a/tests/test-team/template-mgmt-component-tests/template-protected-routes.component.spec.ts
+++ b/tests/test-team/template-mgmt-component-tests/template-protected-routes.component.spec.ts
@@ -1,20 +1,43 @@
 import { test, expect } from '@playwright/test';
-import { TemplateMgmtMessageTemplatesPage } from '../pages/template-mgmt-message-templates-page';
+import { getAppRoutes } from 'helpers/get-app-routes';
+
+import { RoutingChooseEmailTemplatePage } from 'pages/routing/email/choose-email-template-page';
+import { RoutingChooseLargePrintLetterTemplatePage } from 'pages/routing/letter/choose-large-print-letter-template-page';
+import { RoutingChooseMessageOrderPage } from '../pages/routing/choose-message-order-page';
+import { RoutingChooseNhsAppTemplatePage } from 'pages/routing/nhs-app/choose-nhs-app-template-page';
+import { RoutingChooseOtherLanguageLetterTemplatePage } from 'pages/routing/letter/choose-other-language-letter-template-page';
+import { RoutingChooseStandardLetterTemplatePage } from 'pages/routing/letter/choose-standard-letter-template-page';
+import { RoutingChooseTextMessageTemplatePage } from 'pages/routing/sms/choose-sms-template-page';
+import { RoutingCreateMessagePlanPage } from '../pages/routing/create-message-plan-page';
+import { RoutingEditMessagePlanPage } from 'pages/routing/edit-message-plan-page';
+import { RoutingEditMessagePlanSettingsPage } from 'pages/routing/edit-message-plan-settings-page';
+import { RoutingGetReadyToMovePage } from 'pages/routing/get-ready-to-move-page';
+import { RoutingInvalidMessagePlanPage } from 'pages/routing/invalid-message-plan-page';
+import { RoutingMessagePlanCampaignIdRequiredPage } from '../pages/routing/campaign-id-required-page';
+import { RoutingMessagePlansPage } from '../pages/routing/message-plans-page';
+import { RoutingPreviewEmailTemplatePage } from 'pages/routing/email/preview-email-page';
+import { RoutingPreviewLargePrintLetterTemplatePage } from 'pages/routing/letter/preview-large-print-letter-template-page';
+import { RoutingPreviewMessagePlanPage } from 'pages/routing/preview-message-plan-page';
+import { RoutingPreviewNhsAppTemplatePage } from 'pages/routing/nhs-app/preview-nhs-app-page';
+import { RoutingPreviewOtherLanguageLetterTemplatePage } from 'pages/routing/letter/preview-other-language-letter-template-page';
+import { RoutingPreviewSmsTemplatePage } from 'pages/routing/sms/preview-sms-template-page';
+import { RoutingPreviewStandardLetterTemplatePage } from 'pages/routing/letter/preview-standard-letter-page';
+import { RoutingReviewAndMoveToProductionPage } from 'pages/routing';
 import { TemplateMgmtChoosePage } from '../pages/template-mgmt-choose-page';
 import { TemplateMgmtChoosePrintingAndPostagePage } from 'pages/letter/template-mgmt-choose-printing-and-postage-page';
 import { TemplateMgmtCopyPage } from '../pages/template-mgmt-copy-page';
 import { TemplateMgmtCreateEmailPage } from '../pages/email/template-mgmt-create-email-page';
-import { TemplateMgmtUploadLetterPage } from '../pages/letter/template-mgmt-upload-letter-page';
 import { TemplateMgmtCreateNhsAppPage } from '../pages/nhs-app/template-mgmt-create-nhs-app-page';
 import { TemplateMgmtCreateSmsPage } from '../pages/sms/template-mgmt-create-sms-page';
-import { TemplateMgmtDeletePage } from '../pages/template-mgmt-delete-page';
 import { TemplateMgmtDeleteErrorPage } from 'pages/template-mgmt-delete-error-page';
+import { TemplateMgmtDeletePage } from '../pages/template-mgmt-delete-page';
 import { TemplateMgmtEditEmailPage } from '../pages/email/template-mgmt-edit-email-page';
-import { TemplateMgmtEditTemplateCampaignPage } from 'pages/letter/template-mgmt-edit-template-campaign-page';
-import { TemplateMgmtEditTemplateNamePage } from 'pages/letter/template-mgmt-edit-template-name-page';
 import { TemplateMgmtEditNhsAppPage } from '../pages/nhs-app/template-mgmt-edit-nhs-app-page';
 import { TemplateMgmtEditSmsPage } from '../pages/sms/template-mgmt-edit-sms-page';
+import { TemplateMgmtEditTemplateCampaignPage } from 'pages/letter/template-mgmt-edit-template-campaign-page';
+import { TemplateMgmtEditTemplateNamePage } from 'pages/letter/template-mgmt-edit-template-name-page';
 import { TemplateMgmtInvalidTemplatePage } from '../pages/template-mgmt-invalid-tempate-page';
+import { TemplateMgmtMessageTemplatesPage } from '../pages/template-mgmt-message-templates-page';
 import { TemplateMgmtPreviewEmailPage } from '../pages/email/template-mgmt-preview-email-page';
 import { TemplateMgmtPreviewLetterPage } from '../pages/letter/template-mgmt-preview-letter-page';
 import { TemplateMgmtPreviewNhsAppPage } from '../pages/nhs-app/template-mgmt-preview-nhs-app-page';
@@ -24,6 +47,7 @@ import { TemplateMgmtPreviewSubmittedLetterPage } from '../pages/letter/template
 import { TemplateMgmtPreviewSubmittedNhsAppPage } from '../pages/nhs-app/template-mgmt-preview-submitted-nhs-app-page';
 import { TemplateMgmtPreviewSubmittedSmsPage } from '../pages/sms/template-mgmt-preview-submitted-sms-page';
 import { TemplateMgmtRequestProofPage } from '../pages/template-mgmt-request-proof-page';
+import { TemplateMgmtReviewAndApproveLetterTemplatePage } from 'pages/letter/template-mgmt-review-and-approve-letter-template-page';
 import { TemplateMgmtStartPage } from '../pages/template-mgmt-start-page';
 import { TemplateMgmtSubmitEmailPage } from '../pages/email/template-mgmt-submit-email-page';
 import { TemplateMgmtSubmitLetterPage } from '../pages/letter/template-mgmt-submit-letter-page';
@@ -33,40 +57,24 @@ import { TemplateMgmtTemplateSubmittedEmailPage } from '../pages/email/template-
 import { TemplateMgmtTemplateSubmittedLetterPage } from '../pages/letter/template-mgmt-template-submitted-letter-page';
 import { TemplateMgmtTemplateSubmittedNhsAppPage } from '../pages/nhs-app/template-mgmt-template-submitted-nhs-app-page';
 import { TemplateMgmtTemplateSubmittedSmsPage } from '../pages/sms/template-mgmt-template-submitted-sms-page';
-import { TemplateMgmtUploadLetterMissingCampaignClientIdPage } from '../pages/letter/template-mgmt-upload-letter-missing-campaign-client-id-page';
 import { TemplateMgmtUploadBSLLetterTemplatePage } from 'pages/letter/template-mgmt-upload-bsl-letter-template-page';
 import { TemplateMgmtUploadLargePrintLetterTemplatePage } from 'pages/letter/template-mgmt-upload-large-print-letter-template-page';
+import { TemplateMgmtUploadLetterMissingCampaignClientIdPage } from '../pages/letter/template-mgmt-upload-letter-missing-campaign-client-id-page';
+import { TemplateMgmtUploadLetterPage } from '../pages/letter/template-mgmt-upload-letter-page';
 import { TemplateMgmtUploadOtherLanguageLetterTemplatePage } from 'pages/letter/template-mgmt-upload-other-language-letter-template-page';
 import { TemplateMgmtUploadStandardEnglishLetterTemplatePage } from 'pages/letter/template-mgmt-upload-standard-english-letter-template-page';
-import { RoutingChooseMessageOrderPage } from '../pages/routing/choose-message-order-page';
-import { RoutingCreateMessagePlanPage } from '../pages/routing/create-message-plan-page';
-import { RoutingMessagePlanCampaignIdRequiredPage } from '../pages/routing/campaign-id-required-page';
-import { RoutingMessagePlansPage } from '../pages/routing/message-plans-page';
-import { RoutingEditMessagePlanPage } from 'pages/routing/edit-message-plan-page';
-import { RoutingEditMessagePlanSettingsPage } from 'pages/routing/edit-message-plan-settings-page';
-import { RoutingInvalidMessagePlanPage } from 'pages/routing/invalid-message-plan-page';
-import { RoutingChooseEmailTemplatePage } from 'pages/routing/email/choose-email-template-page';
-import { RoutingChooseNhsAppTemplatePage } from 'pages/routing/nhs-app/choose-nhs-app-template-page';
-import { RoutingChooseStandardLetterTemplatePage } from 'pages/routing/letter/choose-standard-letter-template-page';
-import { RoutingChooseTextMessageTemplatePage } from 'pages/routing/sms/choose-sms-template-page';
-import { RoutingPreviewNhsAppTemplatePage } from 'pages/routing/nhs-app/preview-nhs-app-page';
-import { RoutingPreviewEmailTemplatePage } from 'pages/routing/email/preview-email-page';
-import { RoutingPreviewStandardLetterTemplatePage } from 'pages/routing/letter/preview-standard-letter-page';
-import { RoutingPreviewSmsTemplatePage } from 'pages/routing/sms/preview-sms-template-page';
-import { RoutingChooseLargePrintLetterTemplatePage } from 'pages/routing/letter/choose-large-print-letter-template-page';
-import { RoutingChooseOtherLanguageLetterTemplatePage } from 'pages/routing/letter/choose-other-language-letter-template-page';
-import { RoutingPreviewLargePrintLetterTemplatePage } from 'pages/routing/letter/preview-large-print-letter-template-page';
-import { RoutingPreviewOtherLanguageLetterTemplatePage } from 'pages/routing/letter/preview-other-language-letter-template-page';
-import { RoutingGetReadyToMovePage } from 'pages/routing/get-ready-to-move-page';
-import { RoutingPreviewMessagePlanPage } from 'pages/routing/preview-message-plan-page';
-import { RoutingReviewAndMoveToProductionPage } from 'pages/routing';
-import { getAppRoutes } from 'helpers/get-app-routes';
 
 // Reset storage state for this file to avoid being authenticated
 test.use({ storageState: { cookies: [], origins: [] } });
 
 const protectedPages = [
+  RoutingChooseEmailTemplatePage,
+  RoutingChooseLargePrintLetterTemplatePage,
   RoutingChooseMessageOrderPage,
+  RoutingChooseNhsAppTemplatePage,
+  RoutingChooseOtherLanguageLetterTemplatePage,
+  RoutingChooseStandardLetterTemplatePage,
+  RoutingChooseTextMessageTemplatePage,
   RoutingCreateMessagePlanPage,
   RoutingEditMessagePlanPage,
   RoutingEditMessagePlanSettingsPage,
@@ -74,19 +82,13 @@ const protectedPages = [
   RoutingInvalidMessagePlanPage,
   RoutingMessagePlanCampaignIdRequiredPage,
   RoutingMessagePlansPage,
-  RoutingChooseEmailTemplatePage,
-  RoutingChooseNhsAppTemplatePage,
-  RoutingChooseStandardLetterTemplatePage,
-  RoutingChooseLargePrintLetterTemplatePage,
-  RoutingChooseOtherLanguageLetterTemplatePage,
-  RoutingChooseTextMessageTemplatePage,
-  RoutingPreviewMessagePlanPage,
-  RoutingPreviewNhsAppTemplatePage,
   RoutingPreviewEmailTemplatePage,
-  RoutingPreviewStandardLetterTemplatePage,
   RoutingPreviewLargePrintLetterTemplatePage,
+  RoutingPreviewMessagePlanPage,
+  RoutingPreviewNhsAppTemplatePage,
   RoutingPreviewOtherLanguageLetterTemplatePage,
   RoutingPreviewSmsTemplatePage,
+  RoutingPreviewStandardLetterTemplatePage,
   RoutingReviewAndMoveToProductionPage,
   TemplateMgmtChoosePage,
   TemplateMgmtChoosePrintingAndPostagePage,
@@ -94,8 +96,8 @@ const protectedPages = [
   TemplateMgmtCreateEmailPage,
   TemplateMgmtCreateNhsAppPage,
   TemplateMgmtCreateSmsPage,
-  TemplateMgmtDeletePage,
   TemplateMgmtDeleteErrorPage,
+  TemplateMgmtDeletePage,
   TemplateMgmtEditEmailPage,
   TemplateMgmtEditNhsAppPage,
   TemplateMgmtEditSmsPage,
@@ -112,6 +114,7 @@ const protectedPages = [
   TemplateMgmtPreviewSubmittedNhsAppPage,
   TemplateMgmtPreviewSubmittedSmsPage,
   TemplateMgmtRequestProofPage,
+  TemplateMgmtReviewAndApproveLetterTemplatePage,
   TemplateMgmtSubmitEmailPage,
   TemplateMgmtSubmitLetterPage,
   TemplateMgmtSubmitNhsAppPage,
@@ -120,10 +123,10 @@ const protectedPages = [
   TemplateMgmtTemplateSubmittedLetterPage,
   TemplateMgmtTemplateSubmittedNhsAppPage,
   TemplateMgmtTemplateSubmittedSmsPage,
-  TemplateMgmtUploadLetterMissingCampaignClientIdPage,
-  TemplateMgmtUploadLetterPage,
   TemplateMgmtUploadBSLLetterTemplatePage,
   TemplateMgmtUploadLargePrintLetterTemplatePage,
+  TemplateMgmtUploadLetterMissingCampaignClientIdPage,
+  TemplateMgmtUploadLetterPage,
   TemplateMgmtUploadOtherLanguageLetterTemplatePage,
   TemplateMgmtUploadStandardEnglishLetterTemplatePage,
 ];