London riots: Parliament to be recalled
MPs will be recalled from their summer recess on Thursday in the wake of continued disorder across London and other English cities.
David Cameron said all Met Police leave had been cancelled and police on London's streets would rise from 6,000 on Monday to 16,000 on Tuesday.
He interrupted his summer break to chair a meeting of the emergency Cobra committee in Downing Street.
MPs have not been called back during the summer since 2002.
The recall announcement came as some politicians called for tougher measures to be used to quell the violence.
UKIP leader Nigel Farage said troops should be sent in to help restore order, Conservative MP Patrick Mercer suggested water cannons should be used "if necessary" - while London Labour MP Diane Abbott said a curfew should be considered.'Stand together'
But BBC Radio 4's chief political correspondent Norman Smith said Mr Cameron had held back from more extreme measures - possibly guided by police chiefs - to instead pledge a big increase in the number of police officers on the streets and to recall Parliament.
Speaking after the Cobra meeting, Mr Cameron said his office had spoken to Commons Speaker John Bercow, who had agreed to recall Parliament for a day on Thursday.
For David Cameron this could yet prove a pivotal moment that shapes how his premiership is seen.
Aside from national security, ensuring that people can go about their normal lives in a peaceful and secure way is perhaps the core task of any government.
A failure to maintain safety on the streets is therefore a failure of government and Mr Cameron cannot afford for there to be a fourth night of rioting.
Secondly, although Number 10 says Mr Cameron had been monitoring the situation on "an hourly basis" while on holiday, he has appeared well behind the curve of public anger at the rioting.
This matters all the more because it follows what appeared his slow response only a few weeks ago to the hacking saga.
Unlike hacking, however, this cannot be passed off as a Westminster obsession.
Finally, he must be aware that some in his own party and in right-leaning papers will be ready to cite the riots as evidence that the prime minister is not sufficiently focused on law and order.
The stakes for Mr Cameron are high and warm words and a clip on the television news will not be sufficient. Mr Cameron needs to restore order to the streets.
Mr Cameron said he would make a Commons statement - expected at 1130 BST on Thursday - and there would be a debate so "we are all able to stand together in condemnation of these crimes and stand together in determination to rebuild these communities".
Mr Cameron praised police bravery but said it was clear that many more officers were needed alongside more "robust" action.
He said all Metropolitan Police leave had been cancelled and there would be more support from police forces "up and down the country".
He said the government stood on the side of the law abiding and expressed sympathy for homeowners, business people and others left feeling frightened in communities hit by violence.
"This is criminality, pure and simple, and it has to be confronted and defeated," he said.
"People should be in no doubt that we will do everything necessary to restore order to Britain's streets and to make them safe for the law-abiding."
The Commons home affairs committee will also meet in private on Thursday to consider terms of reference for an inquiry into the riots - while Chancellor George Osborne will also update MPs about the global economic situation, expected after Mr Cameron's statement.
There was serious damage in various parts of London on Sunday and Monday nights, with a number of shops looted and buildings set alight. There were also disturbances in Birmingham, Liverpool, Nottingham and Bristol.
The wave of violence began on Saturday night in Tottenham, north London, following a protest against the shooting by police of a local man, 29-year-old Mark Duggan.
Mr Cameron also visited the police command centre in Lambeth, south London to discuss the police response to the disorder and Croydon, where rioters burnt down a furniture store on Monday.
Deputy Prime Minister Nick Clegg visited Birmingham city centre, which also saw disturbances and looting on Monday night. He got a hostile reception from some onlookers but dismissed them as "some trouble makers": "I'm never going to apologise for getting out there and speaking to people and talking to the victims."
London Mayor Boris Johnson also faced angry questions from some business people in Clapham Junction, south London, whose shops had been vandalised on Monday night.
Home Secretary Mrs May, who also ended her summer break early, told BBC Radio 4's Today programme water cannons had not been used in mainland Britain and British policing was based on a model of "policing by consent". But she said "in these circumstances" she would listen to what the police felt they needed to do the job.
Labour MP for Hackney North, Diane Abbott, told the BBC that while a curfew would be "very difficult to impose" it should be considered for some city centres to help "regain control of the streets".
UKIP leader Mr Farage called for military support for the police to help them control the riots and protect people.Water cannons
But Tory MP Patrick Mercer told the BBC: "This is not a military situation, you bring troops in and it starts suggesting a revolution - we are nowhere near that."
He said water cannons should be used "if necessary" - as they had been in Northern Ireland.
Labour leader Mr Miliband, returned to London from a family holiday in Devon, visited Peckham in south-east London, where looting broke out on Monday evening and a bus was set on fire. He called for government support for people whose homes or businesses had been destroyed but said the first priority was to restore public order.
He added: "These people who've committed this violence do not speak for us. I don't think they speak for the people of Peckham. I don't think they speak for the vast majority of people across this country."