Bouncers are being employed by schools to take classes when teachers are not available.

One London school went to a doormen’s agency for “cover supervisors”, who watch over lessons when teachers are away, and gave jobs to two bouncers, one of whom is still at the school.

The National Union of Teachers conference in Cardiff heard that schools were advertising for cover supervisors with military or police experience. Andrew Baisley, a mathematics teacher at a secondary school in Camden, North London, told delegates that head teachers were hiring almost anyone provided they had been checked by the Criminal Records Bureau.

Cover supervisors hand out worksheets and make sure that children behave. They have no teacher training and work is normally set by a teacher who does not stay in the classroom.

Mr Baisley said: “The idea is that it’s about crowd control and childminding. If they’re stern and loud, that’s what is necessary to do the job.”

The wage, half that of supply teachers, was an incentive for supervisors to be used, he said.

In Birmingham an education recruitment agency posted an advert online saying: “Hard core cover supervisors needed now!” and offered £50 to £70 a day. It said: “Aspire People are on the hunt for dynamic, inspiring, hard core cover supervisors. You might be an ex-Marine, prison officer, bouncer, policeman, fireman, sportsman or actor. We need someone who thinks they can get involved in a school environment and control the kids in schools.”

Mr Baisley said: “I know of a school which went to an agency to employ bouncers. They were taken on as permanent members of staff. One ended up with a disciplinary issue within the first term. The bouncers were monitoring lessons. They were big guys who had no teaching experience.”

The school was a secondary in a “not particularly tough area”, he said. “Some adverts for cover supervisors ask for applicants with ex-military or police experience. I think there’s something questionable about thinking that is an appropriate skill for the classroom.”

Cover supervisors are paid up to £20,000 a year; experienced supply teachers earn twice as much. The NUT wants all classes to be taken by qualified teachers when the regular teacher is ill or away preparing for lessons. More cover supervisors are likely to be recruited after September, when rules barring schools from asking teachers to cover for colleagues other than in emergencies come into force.

One teacher discussing the issue on a web forum said that his former school had “full-time security on the corridors and on call for classroom and playground fights. These security were actually nightclub door staff, topping up their income with daytime hours — and believe me they were needed.”

Sarah McCarthy-Fry, the Schools Minister, said: “Heads should ensure that the people they employ have experience and training — and that checks are carried out. Cover supervision should only be a short-term solution.

“Pupils should continue their learning through pre-prepared lessons and exercises supervised by support staff with appropriate skills and training. It is up to heads to determine systems for cover in their schools.”

The behaviour expert Sir Alan Steer, asked by the Government to examine behaviour in schools, is to report this week that disruptive children should be removed to “withdrawal rooms” and taught in isolation.

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