diff --git a/lib/grp.gi b/lib/grp.gi
index 23f54337ed5..ce2037d0332 100644
--- a/lib/grp.gi
+++ b/lib/grp.gi
@@ -1592,12 +1592,13 @@ end );
 ##
 InstallMethod( Socle, "for finite nilpotent groups",
               [ IsGroup ],
-              RankFilter( IsGroup and IsFinite and IsNilpotentGroup ) -
-              RankFilter( IsGroup ),
+              RankFilter( IsGroup and CanComputeSize and IsFinite and
+                          IsNilpotentGroup ) - RankFilter( IsGroup ),
   function(G)
     local H, prodH;
 
-    if not IsFinite(G) or not IsNilpotentGroup(G) then
+    if not CanComputeSize(G) or not IsFinite(G)
+       or not IsNilpotentGroup(G) then
       TryNextMethod();
     fi;