Tear a strip off him and put the fear of god in him so he nevers sets foot in there again and NOT just budge up and give a space on their heated cat blanket
How am i going to keep him out, he's a boy cat and has definately had a little 'spray' in there.
I know I could get a magnetic cat flap but we used to have one at our old house and our two were always pulling their collars off.