Parliament is being recalled on Thursday in response to rioting in England, the prime minister has said.

The government's emergency committee Cobra met on Tuesday after rioting spread across London, with violence flaring in other major cities.

"We will do everything necessary to restore order to Britain's streets and make them safe for the law-abiding," David Cameron said in Downing Street.

More than 16,000 officers will be on London streets on Wednesday, he said.

At least 450 people have been arrested so far, Mr Cameron said.

He condemned what he called "sickening scenes of people looting, vandalising, thieving, robbing".

All Metropolitan Police leave has been cancelled and reinforcements called in from other forces, he said, with treble the number of police than before patrolling the streets of London on Tuesday night.

He told rioters: "You will feel the full force of the law. And if you are old enough to commit these crimes, you are old enough to face the punishment."

The recall of Parliament will allow MPs to "stand together in condemnation of these crimes and to stand together in determination to rebuild these communities", he said.

The prime minister returned early from his holiday in Tuscany to discuss the unrest, which first flared on Saturday after a peaceful protest in Tottenham over the fatal shooting of a man by police.

London has seen a wave of "copycat criminal activity" over the past three days, the Met Police said. More than 69 people have been charged with various offences following hundreds of arrests.

Birmingham, Liverpool, Nottingham and Bristol are among the other cities where violence erupted.

Met Deputy Assistant Commissioner Steven Kavanagh said it was a "shocking and appalling morning for London to wake up to".

"The Met was stretched beyond belief in a way that it has never experienced before," he told BBC Breakfast.

Acting Commissioner Tim Godwin ruled out bringing in the Army to help police tackle the violence, but said: "We will be out there in ever greater numbers tonight."

In other developments:

• Three people are being questioned on suspicion of attempted murder after a police officer was injured by a car in Wembley, north-west London, while trying to stop suspected looters.
• Tube stations in the capital that were closed following the riots have now reopened, apart from Ealing Broadway
• The Tramlink service between East Croydon and Wandle Park has been suspended as a result of the fire at Reeves Corner
• Elsewhere, 100 people have been arrested in Birmingham after scores of youths rampaged through the shopping area, smashing windows and looting from shops
• West Midlands Police said a police station in Holyhead Road in Handsworth, Birmingham, was set on fire
• There were reports of cars being damaged in Manchester and of up to 200 youths with masks roaming through Toxteth in Liverpool
• Police in Bristol said they were dealing with outbreaks of disorder involving about 150 people
• Nottinghamshire Police said a police station was attacked in the St Ann's area and 200 tyres were set alight in the street
• "Small pockets of disorder" were dealt with by police in the Chapeltown area of Leeds overnight

Monday's violence started in Hackney after a man was stopped and searched by police but nothing was found.

Groups of people began attacking the police in Hackney at about 16:20 BST, throwing stones and a bin at officers.

Police cars were smashed by youths armed with wooden poles and metal bars. Looters also smashed their way into shops before being dispersed by police.

Nine police forces from other parts of the country have assisted in providing support to the capital city, as well as the City of London Police and British Transport Police.

However, eyewitnesses have reported that as trouble spread across the city, there were often few police officers around when violence flared.