Barred: The teacher who exposed classroom violence

Angela Mason, 60, went undercover in schools in London and the North-East as a supply teacher, secretly filming scenes of chaos and disruption in 14 comprehensives.

But a panel of teachers at the General Teaching Council in Birmingham decided yesterday that she did not act in the public interest when making Classroom Chaos, a documentary for television channel Five. The GTC has now suspended her for a year.

In an interview with the Evening Standard newspaper, Mrs Mason accused the GTC of being "out of touch with reality".

She said: "It's the reality - ask any teacher what it's like in the classroom today. I've shown this programme to teachers and they've said that's what it's like. I think it's a sad day. A sad day for me but an even sadder day for education."

Mrs Mason, who lives in Hampstead, said that instead of backing the efforts of teachers to instill discipline, the GTC had decided to "shoot the messenger and bury their heads in the sand". She said: "I didn't create the behaviour - the behaviour happened before my eyes.

What I think is so annoying, irrespective of what the GTC says, is that I have had the overwhelming support of pupils, teachers and parents saying, this is the reality of what's going on in schools."

Andrew Baxter - the chairman of the GTC committee - said that secretly filming students amounted to unacceptable professional conduct in all but the most exceptional circumstances.

He said that because Mrs Mason undertook her assignment for a TV programme, she could not use the defence of public interest.

Mr Baxter said: "Her true motivation was to obtain secret film of the pupils for the purposes of a television programme. In that respect we find that her conduct abused the trust of the head teachers, staff and pupils."

Mrs Mason said the verdict betrayed supply teachers in particular. Many of the country's worst-performing schools have a high turnover of permanent staff, which leaves supply teachers trying to cover the curriculum, often in an atmosphere where crowd control is the maximum they can achieve.

Mrs Mason said: "I think it's a really raw deal that they haven't come out fighting in support of supply teachers such as I was, who are sent into the lions' den each day."

Mrs Mason began working as a teacher in the Seventies and then became a TV producer. Before going back to the classroom, she completed an officially approved return to teaching course lasting three weeks.

She has said that in future she may want to become a media studies teacher and the suspension would make that much more difficult.

The GTC, giving its judgment, said Mrs Mason was out of touch with modern behaviour management techniques but she said that only three hours of her three-week refresher course had been devoted to behaviour management.

She said: "I think it is saying that the fault lies with the messenger, not with the system, that it's my fault I don't have up-to-date pupil behaviour management techniques.

"Sorry, but I'm there to teach them subjects I feel passionate about and want them to love. Is there something wrong with that? Do I have to be a guru about management? If it is so important, why are the government themselves not supporting return to teaching folks like me?"

Mrs Mason said her reputation had been "besmirched" by the judgment. But she warned her case had wider implications, as it obscured just how deep-seated a problem the discipline issue had become.

She said: "Society at large has a responsibility, I think parents to some extent have abdicated responsibility and see teachers as the enemy."