diff --git a/.github/workflows/sync_copilot.yml b/.github/workflows/sync_copilot.yml
index 8d51661..7856cc9 100644
--- a/.github/workflows/sync_copilot.yml
+++ b/.github/workflows/sync_copilot.yml
@@ -17,6 +17,6 @@ jobs:
               uses: NHSDigital/eps-copilot-instructions@304ab2f4b7cdc15a1d7c0a0fae5290fad41b2451
               with:
                   copilot_instructions_ref: main
-                  calling_repo_base_branch: master
+                  calling_repo_base_branch: main
                   CREATE_PULL_REQUEST_APP_ID: ${{ secrets.CREATE_PULL_REQUEST_APP_ID }}
                   CREATE_PULL_REQUEST_PEM: ${{ secrets.CREATE_PULL_REQUEST_PEM }}