London mayor Boris Johnson has seized on the violence sweeping England to demand a rethink of Government plans to slash police budgets.
The senior Tory said the rioting had "substantially weakened" an already thin case for cutting funding, which a watchdog has warned could lead to the loss of 16,200 officers.
A beefed-up police presence in the capital helped quell trouble on its streets after three nights of trouble but ugly scenes of looting spread to Manchester, Nottingham and Birmingham.
West Midlands Police launched a murder inquiry when three men died after being hit by a car in the Winson Green area of Birmingham at 1am.
Many victims of the violence have complained of a failure by the police to deal with the disorder but Home Secretary Theresa May has insisted budget cuts will go ahead as planned.
Her Majesty's Inspectorate of Constabulary has suggested around 16,200 police officers will be axed - along with 1,800 community support officers and 16,100 police staff.
Ministers insist the savings can be found through cutting red tape and other functions and do not require reductions in the number of officers available for frontline duty.
As Prime Minister David Cameron chaired a meeting of the Government's emergency committee, Cobra, to discuss the latest developments, Mr Johnson made a dramatic break with party policy.
Unprompted, he told BBC Radio 4's Today: "If you ask me whether I think there is a case for cutting police budgets in the light of these events, then my answer to that would be a 'no',"
The mayor, who is seeking re-election to City Hall next year, went on: "That case was always pretty frail and it has been substantially weakened.
"This is not a time to think about making substantial cuts in police numbers."
Hundreds of marauding thugs played cat and mouse with police in Manchester, smashing shops, setting fire to one premises and looting goods.
More than 100 arrests were made, with a similar number in Birmingham overnight.
Police in Wolverhampton were called to reports of a large group of people in the city centre after shops were attacked.
A mob firebombed a Nottingham police station and college, with more than 90 troublemakers arrested, while in Leicester officers arrested 13 people following trouble in the city centre.
There was also alarm in the South West, with gangs of youths attacking police.
In Gloucester city centre, mounted officers were deployed to combat groups of youths attacking shop windows, some with their faces covered, while a significant fire also broke out in the Brunswick area. Three arrests were made.
And in Bristol, police arrested 19 people following a second night of trouble.
There were also small outbreaks of disorder reported by Thames Valley Police in Reading, Oxford and Milton Keynes, while 200 missile-throwing youths gathered in the south Liverpool area of Toxteth causing disorder and damage, according to Merseyside Police.
Earlier, Metropolitan Police deputy assistant commissioner Stephen Kavanagh told Daybreak: "I have spoken to Acpo (Association of Chief Police Officers) colleagues this morning who co-ordinated the national response.
"There are plenty of resources left in the tank, there are plenty of people available and we will continue to respond as we have to."
He criticised the forming of vigilante groups to defend property.
He told Sky News: "What I don't need is these so-called vigilantes, who appeared to have been drinking too much and taking policing resources away from what they should have been doing - which is preventing the looting."
Mr Johnson's comments appear to directly contradict his own party's current policing strategy.
He said: "If you ask me whether I think there is a case for cutting police budgets... in the light of these events, then my answer to that would be a 'no'.
"I think that case was always pretty frail and it's been substantially weakened.
"I think that this is not a time to think about making substantial cuts in police numbers and I'm looking at the country as a whole."
He said the trouble required "a robust police response".
Commenting on the relative calm on the capital's streets as the violence and looting spread to other major cities in England, he said "there was absolutely no case for complacency about what was achieved last night".
He said: "I think the police did well and I thank them and congratulate them for doing the essential thing of restoring order to the streets of London."
He added: "We will do everything it takes to continue to keep the streets of London completely quiet and to make sure we have no repetition... of what happened, particularly on Monday night."
He revealed that there had been approximately 770 arrests so far, stating that "the hounds" were pursuing those responsible.
Looking back at the events, Mr Johnson said people were "inevitably" going to ask the question "Could the police have gone in harder?"
Mr Johnson labelled the disturbances across the country "a massive own-goal".
"It was just unbelievable to think that here in London you had people who were behaving with a complete absence of restraint and a complete lack of respect for the police."
He said there was now an absence of boundaries and an absence of respect, and called for adults and teachers to be given back the "right to impose authority".
He added: "I think certainly that the response that we saw last night and the robustness that we saw last night needs to be continued."
Referring to the policing position in London, Mr Johnson said: "Obviously we've been able to make significant savings, move money around. and we're able to expand numbers."
He said the events constituted "a massive wake-up call for everybody" and there was a need to address gang culture.