diff --git a/requirements/all.txt b/requirements/all.txt
index eb0354fc80..1bd0d2a989 100644
--- a/requirements/all.txt
+++ b/requirements/all.txt
@@ -3,7 +3,7 @@
 
 # esmpy regridding not available through pip.
 #conda: esmpy>=7.0  (only python=2)
-gdal
+#gdal : under review -- not tested at present
 mo_pack
 nc_time_axis
 pandas
diff --git a/requirements/extensions.txt b/requirements/extensions.txt
index 64a28e91f2..0f3d0e0379 100644
--- a/requirements/extensions.txt
+++ b/requirements/extensions.txt
@@ -6,3 +6,4 @@
 # first.
 
 iris_grib;python_version<"3"  #conda:
+gdal