London Riots
A man with his face covered stands near to a burning car on a street in Hackney in London Reuters

Rioting and looting spread across London on Monday as hooded youths set buildings and cars ablaze, smashed shop windows and hurled bottles and stones at police in a third night of violence in Britain's worst unrest in decades.

Prime Minister David Cameron cut short his holiday to fly home to tackle the violence, which appeared to be led by youths alienated by years of underemployment which left them feeling marginalised even before the economic downturn.

"It's been building up for years. All it needed was a spark," said E. Nan, a young man in a baseball cap surrounded by other youths in Hackney in east London. "We ain't got no jobs, no money ... We heard that other people were getting things for free, so why not us?"

The violence erupted late on Saturday in London's northern Tottenham district when a peaceful protest over the police shooting of a suspect two days earlier turned violent.

By Monday, the violence had spread to parts of the south of the city, including Clapham Junction, one of London's busiest railway junctions, Woolwich in the capital's southeast and the Ealing area of west London.

Attackers also smashed shops and looted property in the city of Birmingham in central England, police said, in the first sign of the riots spreading beyond the capital.

In Hackney, a multi-ethnic area in east London close to the site of next year's Olympic Games, hooded youths set fire to rubbish bins and pushed them down a street towards police, while hurling bottles and bricks.

Many laughed as they ran back when police charged them.

In a street thick with smoke, looters smashed their way into a local shop, stealing whisky and beer. One man grabbed a packet of cereal, another ran off laughing with four bottles of whisky.

"I am from South Africa and it reminds me of the riots there, except the police here are not so rough," said one middle-aged local resident, who declined to give his name.

"But the kids don't have any respect for the police or for property. It's sad for the people who live round here."

In Peckham, a poor area of south London, flames leapt into the air from a torched building and rubble was strewn across the street.

A Reuters witness saw two people breaking into a shop and ripping a 50-inch plasma television off the wall. A youth in a balaclava carried the screen away and received a round of applause from the watching crowd.

Cameron's office said he would cut short his holiday in Italy to chair a crisis meeting, amid growing calls from the public for officials to take control of the situation.

Even before Monday night's violence, police had arrested 215 people, according to Home Secretary Theresa May.

"The violence we've seen, the looting we've seen, the thuggery we've seen, this is sheer criminality ... these people will be brought to justice, they will be made to face the consequences of their actions," she said.

"SENSELESS"

Despite a heavy presence on some streets, police appeared unable to contain the violence as rioters who had initially coordinated through mobile phones and Twitter became increasingly confident.

Monday's looting began long before nightfall when workers were returning home, many of them forced to walk as buses to areas hit by rioting were cancelled.

In Hackney, youths in brown hoods posed for pictures in front of a burning car on a street corner. Others swarmed around a skip full of bricks and gathered them up.

"I don't know why they are doing this," said a middle-aged woman who lived nearby. "It's senseless ... they are just cacking on their own doorstep."

The BBC said the Hackney clashes broke out after police stopped and searched a man.

In Clapham, another Reuters witness saw dozens of youths walking in all directions with looted television sets and other electrical goods. He heard two of them discussing the number of Playstation 3s they had stolen, and shouting at another young man to return and get more.

Looters hid their stolen goods in bins and behind the low walls of the Victorian terraced houses typical of Clapham. A large pile of boxed Blackberry phones rested by one wall.

Government officials branded rioters as opportunistic criminals and said the violence would not affect preparations for next summer's Olympic Games.

But the television pictures of rioting and blazing buildings, combined with disarray in the transport network, were likely to dent the capital's image as Britain struggles to avoid an economic recession.

Youths appeared to have used a free message service on Blackberry mobile phones to coordinate attacks on shops and police.

Research In Motion, the Canadian manufacturer of Blackberry smartphones, said it would work with British authorities, but gave no details on what information, if any, it would give the police.

Some have described the disturbances as a cry for help from poor areas reeling from the government's harsh austerity cuts to tackle a big budget deficit, with youth services and other facilities cut back sharply.

"It's very sad to see ... But kids have got no work, no future and the cuts have made it worse. These kids are from another generation to us and they just don't care," said Anthony Burns, 39, an electrician from Hackney. "You watch. It's only just begun."

Officials said there was no excuse.

"It was needless, opportunistic theft and violence, nothing more, nothing less. It is completely unacceptable," said Deputy Prime Minister Nick Clegg.