Many unruly pupils have trouble at home, impoverished backgrounds, dyslexia, autism, social anxiety and a host of other things. Expelling them solves none of these things.

They may be bullies themselves because of an ongoing toxic culture in the school. That can include the teachers in some cases, who are some of the worst bullies in there. I had one who persecuted me for a speech impediment and humiliated me in front of an entire class of children by making me say tongue twisters.