I had a horrendous lesson, covering for a new school. I told several culprits to sit down. I had one come up continuously, aggressively to me and keep threatening that I hadn't said his name correctly. Hadn't marked the register and couldn't get the lesson going. eventually I said that he should stop clowning around, and when he wouldn't - year 10, GCSE class, I said stop acting like a monkey. Because he simply wouldn't let me get the class going. I do regret coming out with what was unhelpful remark to anyone you are trying to teach, but a black student latched on and accused me of being racist. I had never thought of it as racist language and didn't single out the student because of this. It was supply work at a school and I tried to explain it to the head of year- that three students simply disrupted the class, I did apologise for using terms that didn't seem right. I find that in supply work you are simply used as fodder in schools and the behaviour in some schools simply dominates bad behaviour over students who want to learn.