A 12 year-old boy shields his face as he leaves Manchester magistrates' court after admitting burglary, during the recent riots in Manchester, northern England August 11, 2011. Prime Minister David Cameron, facing a defining crisis of his premiership, promised on Thursday to crack down on street gangs as a national priority and said rioters behind Britain's worst violence in decades would be hunted and punished. REUTERS/Nigel Roddis (BRITAIN - Tags: CIVIL UNREST SOCIETY POLITICS CRIME LAW)