Other teachers did not use the slipper and if they thought you merited corporal punishment would use the cane if senior enough to do so or send you with a note to somebody who was able to cane you.
Well PE teachers were always a strange breed – they lived in an alcove at the back of the gym, rather like some creature out of X Files, and didn’t converse with any other teachers (in fact, I don’t think they actually had a teaching qualification or needed one) except by primordial grunts and were always seen in tracksuits. Their little domain was out of earshot of the rest of the school so if they chose to develop their own regime of unofficial corporal punishment there seemed very little to stop them, the best we could hope for was that they weren’t actually perverts as well (and to be fair I don’t think mine were).