I went to put in a switch drop for a customer this week. This was to control a light already in situ in the loft. So there is a 2gang switch on the landing to control the landing light and a switch for the loft light. After isolating the circuit I removed the switch and the dry line box to discover a twin brown cable tucked behind. This cable went into the loft and up to the light fitting?? Ok I see a DIY job that was just too much for him. I run some T&E from the fitting and clipped in place then run this to an accessable joint box got a feed from landing light and connected everything up. After testing circuit, powered up and he was amazed that the light now worked.. I would have told him of the importance of a neutral but he didn't ask so I took the money and bid him a good day..