its a multi-facted problem. lack of discipline in the home/school, lack of respect for authority, poverty, broken homes, lack of facilities for young people, increased violence in everyday life, bad schooling, the increasing fractionalised society we live in, lack of 'community', increased alcohol/drug use, the 'me-me-me' thatcherist consumerist values.. i could go on.
it's all very well saying these people are "bad" and they should be strung-up/sent to national services, but that is just a daily mail reactionist viewpoint which doesnt contribute anything to the debate
now before you all jump on me, i'm not excusing their behaviour but trying to maybe explain how we got to this situation
unfortunately "yob culture" in an ever-increasing problem in UK society. not one thing can explain it