I'm decorating a bedroom at the moment. When I removed the old wall paper I found a staright line crack running the whole height of the interior plasterborad wall. The crack is about 3mm wide and appears to be the joint between two pasterboards - one side of the crack is sitting proud of the other and I can push it back (if that makes sense) and it looks as if the fixing from the plasterboard to the beeze block wall has failed.
Any ideas on how to fix this please? I guess I can't just fill the crack as the movement of the loose plasterboard will just dislodge it. Any thoughts much appreciated.