By Keith Weir and Stefano Ambrogi
LONDON (Reuters) - Nearly 75 percent of adults charged in last month's riots in England were known criminals with prior convictions, a government minister said on Tuesday, blaming a broken justice system for creating a "feral underclass" of repeat offenders.
Justice Secretary Kenneth Clarke said the worst riots in a generation showed the urgent need to reform a penal system with a "straightforwardly dreadful" record of rehabilitating inmates.
A month on from riots sparked by police shooting a black suspect in the poor north London borough of Tottenham, the Conservative-led coalition government is searching for ways to prevent a repeat of scenes of mayhem that shocked Britons.
The government, in which the smaller Liberal Democrats are junior partners, is talking tough about the rioters, but also trying to reassure voters it is tackling the underlying causes.
It wants courts to continue to process cases swiftly after special weekend and evening sittings last month. It is also studying ways to tackle gangs and 120,000 problem families blamed for playing a part in mass violence and looting.
In an article in the Guardian newspaper, Clarke said the riots showed the danger arising from "a feral underclass, cut off from the mainstream in everything but its materialism."
"It's not yet been widely recognized, but the hardcore of the rioters were in fact known criminals. Close to three quarters of those aged 18 or over charged with riot offences already had a prior conviction," said Clarke, a veteran Conservative.
"That is the legacy of a broken penal system -- one whose record in preventing reoffending has been straightforwardly dreadful," he wrote.
Britain's prison population has swollen to a record high after the riots. Clarke said he wanted to stamp out drugs from jails and pay groups who managed to successfully rehabilitate former inmates.
He was supported by London major Boris Johnson, a fellow Conservative.
"What was going to make you more likely to riot? It was previous contact with the police, and that's the problem that we need to tackle," he told a parliamentary committee.
"We need to ask as a society what is happening to these people (after they have been jailed). How are we changing their lives so they don't come out again and go back to gangs?"
NEW LONDON POLICE CHIEF
Johnson told members of parliament that a new chief for London's Metropolitan Police would be appointed next Monday -- a challenging role after the riots and with the Olympics coming to London next year.
Former chief Paul Stephenson quit in July over criticism of the way the force handled investigations into phone hacking at Rupert Murdoch's News of the World newspaper.
Police lost control of the streets of London and other major English cities as rioting spread across the capital after the initial disturbances in Tottenham on August 6.
The chaos died down after police flooded the streets with officers, but not before five people had been killed and around 3,000 arrested.
With Mayor Johnson and Prime Minister David Cameron away on holiday, police seemed slow to respond when the violence broke out on August 6 -- a summer Saturday night.
"The number of sites of disorder was something we hadn't experienced in the city before -- and that did take us by surprise," acting London police chief Tim Godwin told the parliamentary committee.
He said with the benefit of hindsight he "wished he had had lots more police officers on duty on the Sunday and then into the Monday."
Costs of policing the riots also came under scrutiny. Godwin said that London's police force alone spent an extra 74 million pounds ($119 million) on committing resources to the disturbances, 2 percent of the 3.54 billion pound budget the force will spend on the capital this year.
While Hugh Orde, president of the Association of Chief Police Officers, said, nationally, the cost of providing mutual aid from other forces to help cities tackle the riots had hit 50 million pounds.
Cabinet ministers discussed on Tuesday how to ensure that courts could routinely process cases rapidly -- suggesting that evening and weekend sessions could become the norm.
"Swift justice sends a strong message to people who are committing crimes," the prime minister's spokesman told reporters. ($1 = 0.621 British Pounds)
(Additional reporting by Stephen Mangan)