diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0ffb6d56..84b9d25c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,17 +24,30 @@ jobs:
   # Check if changes were made to the relevant files.
   # Always returns true if running on the default branch, to ensure all changes are throughly checked.
   changes:
-    name: Check for changes in Rust files
+    name: Check for changes
     runs-on: ubuntu-latest
     # Required permissions
     permissions:
       pull-requests: read
     # Set job outputs to values from filter step
+    # These outputs are always true when running after a merge to main, or if the PR has a `run-ci-checks` label.
     outputs:
-      rust: ${{ github.ref_name == github.event.repository.default_branch || steps.filter.outputs.rust }}
-      python: ${{ github.ref_name == github.event.repository.default_branch || steps.filter.outputs.python }}
+      rust: ${{ steps.filter.outputs.rust == 'true' || steps.override.outputs.out == 'true' }}
+      python: ${{ steps.filter.outputs.python == 'true' || steps.override.outputs.out == 'true' }}
     steps:
     - uses: actions/checkout@v4
+    - name: Override label
+      id: override
+      run: |
+        echo "Labels: ${{ github.event.pull_request.labels.*.name }}"
+        echo "Label contains run-ci-checks: ${{ contains( github.event.pull_request.labels.*.name, 'run-ci-checks') }}"
+        if [ "${{ github.event_name == 'pull_request' && contains( github.event.pull_request.labels.*.name, 'run-ci-checks') }}" == "true" ]; then
+          echo "Overriding due to label 'run-ci-checks'"
+          echo "out=true" >> $GITHUB_OUTPUT
+        elif [ "${{ github.ref_name == github.event.repository.default_branch }}" == "true" ]; then
+          echo "Overriding due to running on the default branch"
+          echo "out=true" >> $GITHUB_OUTPUT
+        fi
     - uses: dorny/paths-filter@v3
       id: filter
       with:
@@ -264,6 +277,10 @@ jobs:
     if: ${{ !cancelled() }}
     runs-on: ubuntu-latest
     steps:
+      - name: Debug changes step output
+        run: |
+          echo "Rust: ${{ needs.changes.outputs.rust }}"
+          echo "Python: ${{ needs.changes.outputs.python }}"
       - name: Fail if required checks failed
         # This condition should simply be `if: failure() || cancelled()`,
         # but there seems to be a bug in the github workflow runner.
diff --git a/DEVELOPMENT.md b/DEVELOPMENT.md
index 0ab1acbf..88ad87b2 100644
--- a/DEVELOPMENT.md
+++ b/DEVELOPMENT.md
@@ -111,6 +111,9 @@ We welcome contributions to tket2! Please open [an issue](https://github.com/CQC
 
 PRs should be made against the `main` branch, and should pass all CI checks before being merged. This includes using the [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/) format for the PR title.
 
+Some tests may be skipped based on the changes made. To run all the tests in
+your PR mark it with a 'run-ci-checks' label and push new commits to it.
+
 The general format of a contribution title should be:
 
 ```