Cause your kids are bastards, that's why.

Slowly it dawns on the Brits what their kids are like.
Law creates underclass of child criminals - Times Online

Britain has been condemned as a bleak place for children, where thousands are needlessly criminalised for misdemeanours and where the gap between the education and health of the rich and poor is growing.
...[snip]...
The number of crimes committed by children fell between 2002 and 2006, but, according to research cited by the report, convictions rose by 26 per cent, leading to fears that a young criminal underclass is building. In the past misdemeanours were dealt with by cautions; the trend now is for police to bring charges.
Britain detains more children than any other country in Western Europe, with 2,900 under18s locked up in the past year. Thirty children have died in custody since 1990, yet there has never been a public inquiry into conditions in youth detention centres.

I love the commentators idea that more jail will solve the problem with the youth in the UK. In a culture that glorifies jail time and treats a kid without an ASBO like he runs the projector in science class. Good luck with that.