Children at six schools in England are going to be shown swearing and fighting on TV after they were secretly filmed for a documentary.
A row's broken out about the show, to be shown on Channel Five, because teachers' groups say it's not fair to film kids without their knowledge.
They were filmed by a supply teacher who had cameras hidden in her bag.
None of the children or schools will be identified in the programme, called Classroom Chaos.
The teacher, known by the false name of Sylvia Thomas, went to 18 schools in six months and secretly filmed in six of them.
Programme-makers argued the secret recording was the only way to show the chaos that really goes on in some schools.
"It's an important national story," a spokesman said.
But a spokesman for a teachers' group, called the National Union of Teachers, said the way the programme was made was unacceptable and would not help improve the behaviour of the small number of kids who were very badly behaved.
"We do not need underhand methods for a cheap documentary to expose the problem," they said.
Classroom Chaos will be shown on Channel Five at 8pm on Wednesday 27 April.