Barbara Wilding, the Chief Constable of South Wales, said tribal loyalty had replaced family loyalty in some deprived areas.

And she said custody could only provide a short-term solution, with policies based primarily on enforcement "set on sand".

Her speech, made at the Centre for Crime and Justice Studies at King's College London in May, was reported in The Times, which obtained a transcript.

Ms Wilding reportedly said: "In many of our larger cities, in areas of extreme deprivation, there are almost feral groups of very angry young people.

"Many have experienced family breakdown, and in place of parental and family role models, the gang culture is now established. Tribal loyalty has replaced family loyalty and gang culture based on violence and drugs is a way of life."

Reporting of the remarks comes after the murder of 16-year-old Ben Kinsella, who was stabbed to death in Islington, north London, at the weekend.

He became the 17th teenager to be murdered in London this year.

Ms Wilding, a former Deputy Assistant Commissioner at the Metropolitan Police, said the focus should be on tackling the complex social and economic causes that underlie criminal behaviour.

She said: "In an age of cost-benefit analysis... there is no appetite for solutions that have no visible return and no patience for any which will not bear immediate political fruit."