Re: simple UK light switch wiring diagram
See e.g. http://www.ultimatehandyman.co.uk/diy/electrics/light_fitting/light_ceiling_rose_single.jpg
Plenty of ten minute Youtube videos to explain the concept in more detail.
When the switch is open it has 230v across it, and the light is off. Historically you could connect a low current device (e.g. a couple of neons) across the switch and they'd light when the switch is open (so you could have a backlit switch), but they wouldn't pass enough current to light the main light.
When the switch is closed, no volts across the switch, and in the absence of a neutral in the switch box there is nowhere to derive power for the neons (or whatever).
Have folk seen the light now?
Biting the hand that feeds IT
