Riots that erupted in London neighborhoods over the weekend spread to four other cities yesterday, as hundreds were arrested and at least one person was killed. What began as a protest against the police shooting of Tottenham resident Mark Duggan spread quickly into general rioting and opportunistic looting -- what Prime Minister David Cameron has called "criminality pure and simple." For three days now, buildings and vehicles have been smashed and set on fire, while stores and warehouses were looted. Police have been unable to do much to slow the mayhem. Tonight, some 16,000 police officers will be deployed to London's streets in an effort to quash the worst unrest in the city in decades. Collected here are images of the violence in the U.K. from the past several days.