I wonder how much of that is down to teachers who've spent their whole careers using corporal punishment not having any other methods to deal with behaviour. Honestly, after school detention or writing out lines, for a teenager, is probably worse than a quick smack off the teacher. My Egyptian friend was telling me that when she was in school, if a boy forgot part of his school uniform, they'd give him a big pink sash to wear for the rest of the day. Nothing like a bit of public humiliation, I suppose. The difficulty with any punishment is that it can work in the short term, but in the long term, it can turn the kids off education altogether. I know loads of people in my dad's generation who are clearly intelligent but didn't do well in school. But let's be honest, a lot of corporal punishment on this thread was not well thought through or carefully considered, it's just some dickhead losing his temper and lashing out at someone they have complete power over. It's really no different to a husband hitting his wife, which let's be honest, they probably also did.
Corporal punishment wasn't allowed when I was in school, and even then, there were still huge differences between how well teachers could control a class. In year 9, I remember getting the highest score in the school on the geography exam, so I took it for GCSE. We were given a shite teacher who had no control over the class at all. The classes were constantly disrupted and in the end I left school with a C. I reckon if I'd took history instead, I would have got a higher grade just because the history teacher was so much better at controlling a class.