The scourge of antisocial behaviour among young people could be reversed by teaching their parents how to raise their offspring, researchers claim.

Psychologists in Wales have shown that helping parents to build relationships with children who are overly aggressive, demanding and disobedient, significantly reduces the risk of their developing behavioural disorders and falling into crime, drug abuse and violence as teenagers.

As many as one in 10 children aged from five to 15 has clinically significant behavioural problems and if left untreated, 40 per cent will end up as delinquent teenagers.

The scheme, imported from America, has been so successful it is being rolled out across Wales and to six authorities in England.

Called Incredible Years, it involves teaching parents to listen to their children, praise and reward good behaviour, set rules and impose discipline.

The finding is an embarrassment to ministers whose Sure Start programme launched in 2001, which has cost more than £3bn, has failed to show any effect on reducing behavioural problems in children.

Sure Start offered help to parents in socially disadvantaged areas but much of it had not been tested in trials and an interim report last year found "no significant effect in preventing or reducing conduct disorder.

The Incredible Years programme, developed in Seattle 30 years ago, was implemented by Sure Start staff in 11 centres in North Wales over two and half years.

More than 150 parents took part who had been identified by health visitors as having problem children aged between three and four.

Judy Hutchings of the University of Wales psychology department, who led the study, published on BMJ Journals Online, said: "The Government must deliver programmes known to work and resource them."