The racial disturbances that first rocked Britain's inner cities in 1981 and flared again this year were grim reminders of the nation's increasingly deep social problems. Yet there seemed to be limits to the violence. No police had been killed, and although rioters had thrown rocks and gasoline bombs, they had never used guns. All that changed in a few fierce hours last week when angry rioters, mostly blacks, rampaged through the north London neighborhood of Tottenham. A dozen youths hacked a policeman to death with machetes, and others fired shotguns, rifles and pistols at the police.
The events brought a...