diff --git a/environment.yml b/environment.yml
index b9781b8..30042e5 100644
--- a/environment.yml
+++ b/environment.yml
@@ -15,4 +15,4 @@ dependencies:
   # remove when using conda-forge cf-python
   - udunits2
   - pip:
-    - git+https://github.com/NCAS-CMS/cf-python@main  # edit branch here
+    - git+https://github.com/davidhassell/cfdm.git@h5-read-hdf5-chunks-hack