British Prime Minister David Cameron today vowed to unleash the 'full force' of law on the 'thugs' responsible for one of the worst rioting on Britain's streets, and said the parliament will be recalled for a special session to discuss the conflagration.

Police numbers have also gone up from 6,000 to 16,000 overnight, with officials not ruling out use of water cannons and other extreme riot control methods. All leaves have been cancelled.

Making a statement after chairing a meeting of the government's emergency response committee, Cameron said extra police officers and resources have been made available to the police force in London to deal with the situation.

Cameron, who rushed home after cutting short his holiday in Italy, termed the scenes witnessed on the streets of London and elsewhere as 'appalling' and driven by 'criminality'.

Talking tough, the Prime Minister said the culprits will be brought to bear the consequences of their actions and the government was determined to see that justice is delivered to the law abiding.

To those responsible for the disturbance, he said 'you will feel the full force of law... and if you are old enough to commit these crimes, you are old enough to face punishment'.

"This is criminality pure and simple and it has to be confronted and defeated," he said.

For the past three days, the streets of London have been the centre of violent riots, sparked initially by the killing of a 29-year-old man in police firing last Thursday in Tottenham in north London.

The rioting that started on Saturday has spread to other areas of London and other cities like Birmingham, Bristol and Liverpool, with large scale looting and arson horrifying people.

Cameron said he had met the House of Commons Speaker and the parliament has been recalled for a one-day session on Thursday so that 'we can stand together in condemnation of these crimes and in determination to rebuild these communities'.

Trying to restore confidence in the people, Cameron promised robust action to restore order. He said as many as 450 persons had already been arrested and many more are certain to be rounded up in the coming days.

"People should be in no doubt that we'll do everything necessary to restore order to British streets, and to make them safe for the law abiding," he said. The Prime Minister, who earlier met Metropolitan Police Commissioner and Home Secretary Theresa May, said all Met Police leave had been cancelled, and the number of personnel on London's streets would be up from 6,000 last night to 16,000 by tonight.

"Clear that we need much more police and even more robust action," he acknowleged.

"There will be aid coming from police forces up and down the country and we will do everything necessary to strengthen and assist those police forces that are meeting this disorder".

Terming the scenes of people looting, robbing, vandalising and attacking police officers and even fire crews, as 'sickening', Cameron expressed sympathy for the people who had suffered at the hands of the rioters and whose livelihoods had been affected or potentially detsroyed.

To the people indulging in rioting and arson, he said: "you are not only wrecking the lives of others, and of your own communities, you are potentially ruining your own lives, too".