A policeman stands on Market Street in the city centre during civil disturbances in Manchester, England, Tuesday, Aug. 9 2011. Britain began flooding London's streets with 16,000 police officers Tuesday, nearly tripling their presence as the nation feared its worst rioting in a generation would stretch into a fourth night. The violence has turned buildings into burnt out carcasses, triggered massive looting and spread to other U.K. cities. (AP Photo/Jon Super).