diff --git a/pygenn/genn_groups.py b/pygenn/genn_groups.py
index d0a8b1c685..93c4f9a395 100644
--- a/pygenn/genn_groups.py
+++ b/pygenn/genn_groups.py
@@ -293,29 +293,22 @@ def _load_egp(self, egp_dict=None, egp_suffix=""):
                                                             egp_data.type)
                 # Copy values
                 egp_data.view[:] = egp_data.values
-            else:
-                if egp_data.values is None:
-                    cname = self.__class__.__name__
-                    mname = self.name
-                    raise Exception(f"Extra global parameter {egp_name} "
-                                    f"for {mname} ({cname}) can not be set "
-                                    f"to None, it should be {egp_data.type}")
-                else:
-                    # Allocate memory
-                    self._model._slm.allocate_extra_global_param(
-                        self.name, egp_name + egp_suffix, len(egp_data.values))
-
-                    # Assign view
-                    egp_data.view = self._assign_ext_ptr_array(egp_name + egp_suffix,
-                                                               len(egp_data.values), 
-                                                               egp_data.type)
-
-                    # Copy values
-                    egp_data.view[:] = egp_data.values
-
-                    # Push egp_data
-                    self._model._slm.push_extra_global_param(
-                        self.name, egp_name + egp_suffix, len(egp_data.values))
+            elif egp_data.values is not None:
+                # Allocate memory
+                self._model._slm.allocate_extra_global_param(
+                    self.name, egp_name + egp_suffix, len(egp_data.values))
+
+                # Assign view
+                egp_data.view = self._assign_ext_ptr_array(egp_name + egp_suffix,
+                                                           len(egp_data.values), 
+                                                           egp_data.type)
+
+                # Copy values
+                egp_data.view[:] = egp_data.values
+
+                # Push egp_data
+                self._model._slm.push_extra_global_param(
+                    self.name, egp_name + egp_suffix, len(egp_data.values))
 
     def _load_var_init_egps(self, var_dict=None):
         # If no variable dictionary is specified, use standard one