Prime Minister David Cameron is under growing pressure to abandon plans to cut police funding, part of the government's austerity drive, after the worst looting and rioting in decades hit cities across England.
The Conservative Party leader said "the lawless minority" would be hunted down and punished, and blamed the police for their initial response.
Trouble spread from the capital to several other cities over four chaotic nights, severely stretching police resources.
Britain is divided over what caused the looting and arson, but many fear any reduction in police numbers as part of the government's deep public spending cuts would leave the country exposed if more trouble erupts.
Community leaders and some commentators say poverty, unemployment and a sense of exclusion among many young people cannot be ignored, and public sector cuts are likely to hit the poorest in society hardest.
Ed Miliband, leader of the opposition Labour Party, took care not to blame the government's planned cuts directly for the violence, but told the BBC: "The cuts that are being made are very bad for our society."
Cameron blamed the violence on a minority of opportunistic criminals and on society's failings. "When you have deep moral failures you don't hit them with a wall of money," he told parliament in an emergency debate.
Police chiefs were unimpressed with Cameron's criticism of their officers' initial response. "The police faced an unprecedented situation, unique circumstances," said Hugh Orde, president of the Association of Chief Police Officers.
Orde said "honest conversations" were needed with the government about its spending plans. "It's the 20 percent cuts in the present spending period that will lead to less police officers, we should be very clear about that."
Cameron's center-right Conservatives took power in May 2010 in coalition with the smaller, centrist Liberal Democrats, promising to cut spending to reduce a budget deficit that peaked at more than 10 percent of gross domestic product.
Finance minister George Osborne said on Thursday Britain's deficit reduction measures were an example to the rest of Europe, but many fear job losses, benefit cuts and reduced services.
Labour, in power for 13 years until May 2010 under Tony Blair and Gordon Brown, have repeatedly said the coalition's planned cuts are too big, too soon, and will stunt the economy.
"The events of the last few days have been a stark reminder to us all that police on our streets make our communities safer and make the public feel safer," Miliband told parliament.
London's mayor, Boris Johnson, has called for a rethink over the police cuts.
Britons were appalled at the scenes on their streets, from the televised mugging of a badly beaten Malaysian teenager by people pretending to help him, to a Polish woman photographed leaping from a burning building.
A 68-year-old man who was attacked as he tried to put out a fire set by rioters in London on Monday night died of his injuries, officials said on Friday. Police have launched a murder inquiry.
The scale and ferocity of the rioting -- not only in inner-city areas but also in some middle-class suburbs -- battered Britain's image as a civilized and peaceful society.
Footage of looters kicking in shop windows and stealing everything from baby clothes to food and television sets was repeated for days on rolling news channels around the world.
The unrest flared first in London after police shot dead a black man and refused to give his relatives information about the incident. A local protest then developed into widespread looting and violence.
But social strains have been growing in Britain for some time, with the economy struggling to clamber out of an 18-month recession, one in five young people out of work and high inflation squeezing incomes and hitting the poor hardest.
Some of the looters spoke of taking a stand against "the system" and picked out the recent scandal of lawmakers' fraudulent expenses claims and huge bonuses paid to bankers.
Morale in London's police force has been dented by the loss of its leader and other senior figures in recent weeks in the fallout from the phone-hacking and bribery allegations at Rupert Murdoch's British newspapers.
As courts stayed open through the night to deal with the hundreds of people charged over the looting and violence, police flooded the streets to maintain an uneasy peace.
Steve Kavanagh, deputy assistant commissioner of the Metropolitan Police, said 16,000 officers would remain on duty in the capital on Friday. That is their biggest peacetime deployment and compares with a normal figure of around 2,500.