This trick was tried at a place I worked for, they installed a camera in a P.I.R. sensor to try and get rid of lad (who wanted sacking anyway-lazy twat) who they couldn't catch up to no good, they caught him on film, but it was kicked out at a tribunal as they have to inform you that cameras are in use under "the protection of civil liberties act". As far as I can remember that's what happened.
It didn't get the lad his job back, as they can't be forced to do that anymore, but he did get a fair pay off.
At the end of the day if your boss wants rid of you or anyone else, all he has to d