Writing in The Guardian, Ken Clarke revealed that 75 per cent of the over-18s charged with involvement in the riots had criminal records.

The justice secretary said the outbreak of unrest was down to a lack of punishment for the UK's "feral underclass" and called for government action to tackle the "appalling social deficit" the disorder had uncovered.

He said the riots were a further sign the penal system in its current form is not working, and criticised the rate of reoffending as "straightforwardly dreadful". He said the riots made his efforts to reform justice all the more important.

Mr Clarke said sentencing for riot offenders - which has been criticised as being too harsh by some lawyers and human rights organisations - had been "about right", but added: "In my view, the riots can be seen in part as an outburst of outrageous behaviour by the criminal classes - individuals and families familiar with the justice system, who haven't been changed by their past punishments."

In total more than 1,500 people have now appeared in court over the riots.

Met Police praised for riot handling

The home affairs select committee is today hearing evidence on the wave of violence and theft from witnesses including Mayor of London Boris Johnson and senior Met officers such as Acting Commissioner Tim Godwin.

Boris Johnson told MPs Mr Clarke was "on the right lines this morning when he talked about problems in the justice system".

He said: "Seventy-five per cent of those arrested do have criminal records. 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?"

Boris Johnson also told the committee London dealt with the riots well, if compared with other similar situations, such as the Paris riots in 2005.

Radical changes to penal system

Justice Secretary Kenneth Clarke suggests turning prisons into areas of "productive hard work" and "toughening community sentences" in a bid to reduce high rates of reoffending.

Writing in today's Guardian Clarke was responding to news that 75 per cent of those adults involved in the August riots had previous convictions.

He argued that not putting systems in place to reduce the risk of people committing new crimes once released from prison "did not make for intelligent sentencing."

Clarke pledged to reduce reoffending rates, saying he wanted to introduce radical changes to "focus our penal system relentlessly on proper, robust punishment and the reduction of reoffending."

"This means making our jails places of productive hard work, addressing the scandal of drugs being readily available in many of our prisons and toughening community sentences so that they command public respect"

Community sentences are generally given out for minor offences and are intended to benefit the local area. The details of the sentence are at the discretion of the judge, but involve a combination of unpaid community work, skills training, treatment programmes for health issues like addiction or mental health conditions and some restrictions on lifestyle, for example a curfew.

As an alternative to short-term prison sentences, a community sentence is marginally less likely to lead to reoffending, according to figures from the Ministry of Justice.

However according to Graham Beech, strategic development director at Nacro, the crime reduction charity, community sentences under the current system are not enforced strongly enough, meaning that offenders stop taking part before finishing a programme that would help with their rehabilitation.

"We know that many people drop out before they finish their sentence," he says. "The net effect is that the sentence that was imposed is not completed: the work that would change attitudes and behaviour has not been completed. Community sentencing needs to restrict the offender's liberty in such a way that they can comply with programmes that will make them less likely to offend again in the future."

Proposals to engage prisoners in work programmes were generally welcomed by rehabilitation charities and prisoner groups. Mark Johnson, ex-offender and founder of the rehabilitation charity User Voice, said he agreed in theory, but was concerned about the kind of work intended.

"We need to ask what will the work teach the prisoner?" he says. "If it's just work for private companies, like screwing on light-bulbs, is that meaningful work that will help prisoners in the long run?"

At the moment, short term sentences, with little scope for re-skilling prisoners, run the risk of taking the responsibility of change away from the prisoner, says Mr Beech: "[Short term sentences] do not give anyone the time to work on some deeply entrenched and complex issues."

Kenneth Clarke's proposals, which echo his green paper on reoffending, also recognised the importance of working with private and voluntary groups outside the penal system who help with the rehabilitation of former prisoners.

Jenny Leadley, criminal justice researcher at the New Economics Foundation (NEF) think-tank welcomed the inclusion of charities and organisations who work with offenders, in the debate about reoffending. "The criminal justice system is not rehabilitating anyone," she says. "Other charities and groups are just as important as the probation and prison services."

Prisoners who have difficulty getting employment and accommodation on release from prison had a reoffending rate of 74% during the year of their release, according to a survey by the Ministry of Justice, compared to 43% for those who have no problems in these areas.