I was recently called out for a reported minor electric shock incident.  Discovered a Double Socket Outlet plastic front had been incorrectly replaced by a DIYer. Worse still the DIYer must have been colour blind and or had  bad eyesight because the wiring into the back of the socket was exactly wrong;  The live wire was screwed into the Earth terminal! Luckily no one was injured, including me.  It was a quick job to repair and test. All safe now.