The Conservative leader said that young people should not be demonised and called for a more balanced strategy in which the State’s duty to punish bad behaviour was combined with society’s role in encouraging good behaviour.

“If all we have to say to those kids is that you’re feral, that you deserve an ASBO, that you should be in custody — we will simply be reacting to youth crime instead of reducing it,” he said.

“Tell a 16-year-old boy, abandoned by his father, neglected by his mother, on drugs, dyslexic, hyper-active . . . tell that boy it’s all his own fault when he ends up in Feltham [the young offenders institution].”

He said Tony Blair had broken his promise to be “tough on crime and tough on the causes of crime” but if governments did not tackle the causes of crime they would never have a safer society.

The Conservatives are attempting to reposition themselves as a more compassionate party than Labour and better in touch with the problems facing young people today.

Labour disparaged Mr Cameron’s speech, saying it amounted to “love a lout”, another version of his controversial “hug a hoodie” speech.

Mr Cameron was speaking as new research on the lives of British teenagers uncovered a debauched life of drinking, fighting and underage sex among today’s 15-year-olds.

The study, conducted by the Institute for Public Policy Research (IPPR), said that a serious breakdown in the relationship between children and adults in Britain was to blame, a rift not witnessed in comparable European countries.

Many teenagers in Britain spend almost all their free time hanging round with friends learning from their peers, rather than from adults, how to behave.

Only two thirds of British teenagers eat any meals sitting at a table with their parents compared with 93 per cent in Italy and 89 per cent in France.

Instead, 59 per cent of boys in Scotland and 45 per cent in England spend four or more evenings with their friends.

Amost half (44 per cent) of 15-year-olds have been in a physical fight in the past year compared with just 28 per cent in Germany.

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