diff --git a/.github/workflows/python-publish.yml b/.github/workflows/python-publish.yml
index 49d8b2e..c6a6a31 100644
--- a/.github/workflows/python-publish.yml
+++ b/.github/workflows/python-publish.yml
@@ -30,6 +30,7 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install pypa/build
+      shell: bash -l {0}
       run: >-
         source /home/firedrake/firedrake/bin/activate
         python3 -m