diff --git a/.github/actions/build-docs/action.yml b/.github/actions/build-docs/action.yml
index d7f1ff7..2467307 100644
--- a/.github/actions/build-docs/action.yml
+++ b/.github/actions/build-docs/action.yml
@@ -8,8 +8,8 @@ runs:
   using: "composite"
   steps:
     - name: Checkout
-      uses: actions/checkout@v4
-    - uses: actions/setup-node@v4
+      uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+    - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
       with:
         node-version: 22
     - name: Npm cli install
@@ -17,7 +17,7 @@ runs:
       run: npm ci
       shell: bash
     - name: Setup Ruby
-      uses: ruby/setup-ruby@v1.180.1
+      uses: ruby/setup-ruby@3783f195e29b74ae398d7caca108814bbafde90e # v1.180.1
       with:
         ruby-version: "3.2" # Not needed with a .ruby-version file
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
@@ -25,7 +25,7 @@ runs:
         working-directory: "./docs"
     - name: Setup Pages
       id: pages
-      uses: actions/configure-pages@v5
+      uses: actions/configure-pages@983d7736d9b0ae728b81ab479565c72886d7745b # v5
     - name: Build with Jekyll
       working-directory: ./docs
       # Outputs to the './_site' directory by default
@@ -36,7 +36,7 @@ runs:
         JEKYLL_ENV: production
     - name: Upload artifact
       # Automatically uploads an artifact from the './_site' directory by default
-      uses: actions/upload-pages-artifact@v3
+      uses: actions/upload-pages-artifact@56afc609e74202658d3ffba0e8f6dda462b719fa # v3
       with:
         path: "docs/_site/"
         name: jekyll-docs-${{ inputs.version }}
diff --git a/.github/actions/create-lines-of-code-report/action.yaml b/.github/actions/create-lines-of-code-report/action.yaml
index 86396f7..0f149dd 100644
--- a/.github/actions/create-lines-of-code-report/action.yaml
+++ b/.github/actions/create-lines-of-code-report/action.yaml
@@ -32,7 +32,7 @@ runs:
       run: zip lines-of-code-report.json.zip lines-of-code-report.json
     - name: "Upload CLOC report as an artefact"
       if: ${{ !env.ACT }}
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
       with:
         name: lines-of-code-report.json.zip
         path: ./lines-of-code-report.json.zip
@@ -44,7 +44,7 @@ runs:
         echo "secrets_exist=${{ inputs.idp_aws_report_upload_role_name != '' && inputs.idp_aws_report_upload_bucket_endpoint != '' }}" >> $GITHUB_OUTPUT
     - name: "Authenticate to send the report"
       if: steps.check.outputs.secrets_exist == 'true'
-      uses: aws-actions/configure-aws-credentials@v4
+      uses: aws-actions/configure-aws-credentials@7474bc4690e29a8392af63c5b98e7449536d5c3a # v4
       with:
         role-to-assume: arn:aws:iam::${{ inputs.idp_aws_report_upload_account_id }}:role/${{ inputs.idp_aws_report_upload_role_name }}
         aws-region: ${{ inputs.idp_aws_report_upload_region }}
diff --git a/.github/actions/scan-dependencies/action.yaml b/.github/actions/scan-dependencies/action.yaml
index 1000df1..2d47d0b 100644
--- a/.github/actions/scan-dependencies/action.yaml
+++ b/.github/actions/scan-dependencies/action.yaml
@@ -32,7 +32,7 @@ runs:
       run: zip sbom-repository-report.json.zip sbom-repository-report.json
     - name: "Upload SBOM report as an artefact"
       if: ${{ !env.ACT }}
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
       with:
         name: sbom-repository-report.json.zip
         path: ./sbom-repository-report.json.zip
@@ -47,7 +47,7 @@ runs:
       run: zip vulnerabilities-repository-report.json.zip vulnerabilities-repository-report.json
     - name: "Upload vulnerabilities report as an artefact"
       if: ${{ !env.ACT }}
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
       with:
         name: vulnerabilities-repository-report.json.zip
         path: ./vulnerabilities-repository-report.json.zip
@@ -58,7 +58,7 @@ runs:
       run: echo "secrets_exist=${{ inputs.idp_aws_report_upload_role_name != '' && inputs.idp_aws_report_upload_bucket_endpoint != '' }}" >> $GITHUB_OUTPUT
     - name: "Authenticate to send the reports"
       if: steps.check.outputs.secrets_exist == 'true'
-      uses: aws-actions/configure-aws-credentials@v4
+      uses: aws-actions/configure-aws-credentials@7474bc4690e29a8392af63c5b98e7449536d5c3a # v4
       with:
         role-to-assume: arn:aws:iam::${{ inputs.idp_aws_report_upload_account_id }}:role/${{ inputs.idp_aws_report_upload_role_name }}
         aws-region: ${{ inputs.idp_aws_report_upload_region }}
diff --git a/.github/actions/sync-template-repo/action.yaml b/.github/actions/sync-template-repo/action.yaml
index b5f32d8..1b2ccdb 100644
--- a/.github/actions/sync-template-repo/action.yaml
+++ b/.github/actions/sync-template-repo/action.yaml
@@ -8,7 +8,7 @@ runs:
   using: "composite"
   steps:
     - name: "Check out template repository"
-      uses: actions/checkout@v4
+      uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       with:
         repository: NHSDigital/nhs-notify-repository-template
         path: nhs-notify-repository-template
diff --git a/.github/workflows/cicd-1-pull-request.yaml b/.github/workflows/cicd-1-pull-request.yaml
index 2f8d20c..52ee997 100644
--- a/.github/workflows/cicd-1-pull-request.yaml
+++ b/.github/workflows/cicd-1-pull-request.yaml
@@ -29,7 +29,7 @@ jobs:
       does_pull_request_exist: ${{ steps.pr_exists.outputs.does_pull_request_exist }}
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Set CI/CD variables"
         id: variables
         run: |
diff --git a/.github/workflows/cicd-3-deploy.yaml b/.github/workflows/cicd-3-deploy.yaml
index 5230577..bc65231 100644
--- a/.github/workflows/cicd-3-deploy.yaml
+++ b/.github/workflows/cicd-3-deploy.yaml
@@ -37,7 +37,7 @@ jobs:
       # tag: ${{ steps.variables.outputs.tag }}
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Set CI/CD variables"
         id: variables
         run: |
@@ -70,8 +70,7 @@ jobs:
     needs: metadata
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
-
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Get version"
         id: get-asset-version
         shell: bash
@@ -103,13 +102,13 @@ jobs:
         run: |
           gh release download ${{steps.get-asset-version.outputs.release_version}} -p jekyll-docs-*.tar --output artifact.tar
 
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: jekyll-docs-${{steps.get-asset-version.outputs.release_version}}
           path: artifact.tar
 
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4
         with:
           artifact_name: jekyll-docs-${{steps.get-asset-version.outputs.release_version}}
diff --git a/.github/workflows/manual-combine-dependabot-prs.yaml b/.github/workflows/manual-combine-dependabot-prs.yaml
index fbf0409..3e311ac 100644
--- a/.github/workflows/manual-combine-dependabot-prs.yaml
+++ b/.github/workflows/manual-combine-dependabot-prs.yaml
@@ -15,7 +15,7 @@ jobs:
     steps:
       - name: combine-prs
         id: combine-prs
-        uses: github/combine-prs@v5.2.0
+        uses: github/combine-prs@2909f404763c3177a456e052bdb7f2e85d3a7cb3 # v5.2.0
         with:
           ci_required: false
           labels: dependencies
diff --git a/.github/workflows/release_created.yaml b/.github/workflows/release_created.yaml
index bac7f06..3d928a7 100644
--- a/.github/workflows/release_created.yaml
+++ b/.github/workflows/release_created.yaml
@@ -19,8 +19,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5.0.0
-
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
       - name: "Package and Publish Terraform modules"
         run: |
           ARTIFACTS_DIR="$PWD/../../artifacts"
diff --git a/.github/workflows/scheduled-repository-template-sync.yaml b/.github/workflows/scheduled-repository-template-sync.yaml
index 548495f..acfc025 100644
--- a/.github/workflows/scheduled-repository-template-sync.yaml
+++ b/.github/workflows/scheduled-repository-template-sync.yaml
@@ -16,8 +16,7 @@ jobs:
 
     steps:
     - name: Check out the repository
-      uses: actions/checkout@v4
-
+      uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
     - name: Sync repository template
       uses: ./.github/actions/sync-template-repo
       with:
@@ -25,7 +24,7 @@ jobs:
 
     - name: Create Pull Request
       if: ${{ !env.ACT }}
-      uses: peter-evans/create-pull-request@v7.0.8
+      uses: peter-evans/create-pull-request@271a8d0340265f705b14b6d32b9829c1cb33d45e # v7.0.8
       with:
         token: ${{ secrets.GITHUB_TOKEN }}
         commit-message: Drift from template
diff --git a/.github/workflows/scorecard.yml b/.github/workflows/scorecard.yml
index 5552785..5264140 100644
--- a/.github/workflows/scorecard.yml
+++ b/.github/workflows/scorecard.yml
@@ -59,7 +59,7 @@ jobs:
       # Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
       # format to the repository Actions tab.
       - name: "Upload artifact"
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: SARIF file
           path: results.sarif
diff --git a/.github/workflows/stage-1-commit.yaml b/.github/workflows/stage-1-commit.yaml
index eda2c98..28f9c65 100644
--- a/.github/workflows/stage-1-commit.yaml
+++ b/.github/workflows/stage-1-commit.yaml
@@ -39,7 +39,7 @@ jobs:
     timeout-minutes: 2
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0 # Full history is needed to scan all commits
       - name: "Scan secrets"
@@ -50,7 +50,7 @@ jobs:
     timeout-minutes: 2
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0 # Full history is needed to compare branches
       - name: "Check file format"
@@ -61,7 +61,7 @@ jobs:
     timeout-minutes: 2
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0 # Full history is needed to compare branches
       - name: "Check Markdown format"
@@ -75,7 +75,7 @@ jobs:
         contents: write
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0 # Full history is needed to compare branches
       - name: "Check to see if Terraform Docs are up-to-date"
@@ -96,7 +96,7 @@ jobs:
     timeout-minutes: 2
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0 # Full history is needed to compare branches
       - name: "Check English usage"
@@ -107,7 +107,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0 # Full history is needed to compare branches
       - name: "Check TODO usage"
@@ -119,8 +119,7 @@ jobs:
       terraform_changed: ${{ steps.check.outputs.terraform_changed }}
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
-
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Check for Terraform changes"
         id: check
         run: |
@@ -143,9 +142,9 @@ jobs:
     if: needs.detect-terraform-changes.outputs.terraform_changed == 'true'
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Setup ASDF"
-        uses: asdf-vm/actions/setup@v4
+        uses: asdf-vm/actions/setup@b7bcd026f18772e44fe1026d729e1611cc435d47 # v4
       - name: "Lint Terraform"
         uses: ./.github/actions/lint-terraform
   trivy:
@@ -156,9 +155,9 @@ jobs:
     if: needs.detect-terraform-changes.outputs.terraform_changed == 'true'
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Setup ASDF"
-        uses: asdf-vm/actions/setup@v4
+        uses: asdf-vm/actions/setup@b7bcd026f18772e44fe1026d729e1611cc435d47 # v4
       - name: "Perform Setup"
         uses: ./.github/actions/setup
       - name: "Trivy Scan"
@@ -172,7 +171,7 @@ jobs:
     timeout-minutes: 2
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Count lines of code"
         uses: ./.github/actions/create-lines-of-code-report
         with:
@@ -191,7 +190,7 @@ jobs:
     timeout-minutes: 2
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Scan dependencies"
         uses: ./.github/actions/scan-dependencies
         with:
diff --git a/.github/workflows/stage-2-test.yaml b/.github/workflows/stage-2-test.yaml
index efcb2ac..4531030 100644
--- a/.github/workflows/stage-2-test.yaml
+++ b/.github/workflows/stage-2-test.yaml
@@ -39,7 +39,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Run unit test suite"
         run: |
           make test-unit
@@ -52,7 +52,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Run linting"
         run: |
           make test-lint
@@ -66,7 +66,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Run test coverage check"
         run: |
           make test-coverage
@@ -83,7 +83,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0 # Full history is needed to improving relevancy of reporting
       - name: "Perform static analysis"
diff --git a/.github/workflows/stage-3-build.yaml b/.github/workflows/stage-3-build.yaml
index 7d7bdbc..2b5995c 100644
--- a/.github/workflows/stage-3-build.yaml
+++ b/.github/workflows/stage-3-build.yaml
@@ -39,7 +39,7 @@ jobs:
     timeout-minutes: 3
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Build artefact 1"
         run: |
           echo "Building artefact 1 ..."
@@ -56,7 +56,7 @@ jobs:
     timeout-minutes: 3
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Build artefact n"
         run: |
           echo "Building artefact n ..."
diff --git a/.github/workflows/stage-4-acceptance.yaml b/.github/workflows/stage-4-acceptance.yaml
index d554f98..3d65b93 100644
--- a/.github/workflows/stage-4-acceptance.yaml
+++ b/.github/workflows/stage-4-acceptance.yaml
@@ -39,7 +39,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Create infractructure"
         run: |
           echo "Creating infractructure..."
@@ -56,7 +56,7 @@ jobs:
     timeout-minutes: 10
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Run contract test"
         run: |
           make test-contract
@@ -70,7 +70,7 @@ jobs:
     timeout-minutes: 10
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Run security test"
         run: |
           make test-security
@@ -84,7 +84,7 @@ jobs:
     timeout-minutes: 10
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Run UI test"
         run: |
           make test-ui
@@ -98,7 +98,7 @@ jobs:
     timeout-minutes: 10
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Run UI performance test"
         run: |
           make test-ui-performance
@@ -112,7 +112,7 @@ jobs:
     timeout-minutes: 10
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Run integration test"
         run: |
           make test-integration
@@ -126,7 +126,7 @@ jobs:
     timeout-minutes: 10
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Run accessibility test"
         run: |
           make test-accessibility
@@ -140,7 +140,7 @@ jobs:
     timeout-minutes: 10
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Run load tests"
         run: |
           make test-load
@@ -164,7 +164,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: "Tear down environment"
         run: |
           echo "Tearing down environment..."