A mother said her daughter's wayward behaviour was transformed after she featured in a television show on teaching unruly pupils.

Sam Hull said her daughter Grace's obnoxious and disrespectful behaviour was turned around after she was filmed for Channel 4's new education series The Unteachables.

The four-part programme, which began last night, pits three top teachers and a psychologist against 16 disaffected teenagers.

They try out both traditional teaching styles and radical and progressive methods to try to get through to the class.

Grace, 14, was one of six pupils from Varndean School in Brighton selected to take part in the education experiment run by Ted Wragg, emeritus professor of education at Exeter University.

Last night's opening installment showed the youngsters staying up until 6am, damaging property and threatening to set a barn on fire with a lighter.

However, Mrs Hull, who lives with her husband Simon, Grace, and younger children Ellis, 12 and Stan, two, in Chester Terrace, Brighton, said the show had had a positive effect on her daughter.

She said that Grace, who was excluded four times last year for persistent disruptive behaviour, started to rebel when she joined a new group of friends.

She said: "She was completely detached. She had lost respect for everything and was going down a really bad road.

"She was totally unapproachable and volatile.

"I tried talking to her but it felt like we were losing her.

"I was desperate for something to get through.

"Now she still has a short fuse but her whole attitude has changed.

"One of the teachers made her realise she wasn't thick and she had something to give.

"It's as if she realised it's worth trying again.

"It's going to be horrendous watching the programmes but it shows that you don't have to come from an unstable background to have the problems we have been through."

Andy Schofield, headteacher of Varndean in Balfour Road, where 75 per cent of students gained five A* to C grades this year, said: "All schools have so-called unteachable pupils and it was actually very competitive to get involved.

"I thought that if it made a difference to only one pupil it would be worthwhile but it has had a very positive effect overall.

"We find most disruptive behaviour occurs in Year 9. Often it is only a phase but the pupils who took part in the programme seemed to come out of that phase much quicker than they would otherwise.

"It proves no pupil is unteachable and that teachers can reach even the most challenging students."

He said some of the behaviour in the programme was inconsistent with real classroom antics as pupils acted up for the cameras.

He said: "There was a lot of bravado. The kids love the attention and so they played up. A lot of what they said needs to be taken with a pinch of salt.

"These kids are in school, we do engage with them and they stay in line for 99 per cent of the time."