Peter Cuthbertson: Last year saw 91,000 cases of serious, repeat offenders avoiding prison

Peter recently founded the Centre for Crime Prevention, a new campaign for the proper use of prisons and front line policing. Follow Peter on Twitter.

It's not often one gets through a media debate on prisons without hearing a particular trope: "Prison should be reserved for serious, repeat offenders."

Well, maybe, but as Nick Herbert notes, "Those who say that prison should be reserved for serious or serial offenders tend to ignore the fact that it already is." In my report today, I investigate the degree to which, far from there there being more prisoners than there are serious, repeat offenders, there are far more serious, repeat offenders than prison cells.

Two figures do much to highlight the grim reality. They are taken from the share of offenders guilty of 'more serious' indictable offences such as violence against the person, sexual offences, robberty and theft.

• In 2011/12, 68,100 received a penalty other than prison for a serious offence despite 15 or more previous convictions or cautions. As a total of 108,119 serious offenders had 15 or more previous convictions/cautions, this means 63% of them avoided prison.
• The same year, the number of serious offenders who avoided prison despite more than 10 previous convictions/cautions was 91,032. This means 65% of them avoided prison - and is a figure higher than the total prison population of 83,825.

I could go on, and the report does, but these figures alone should do much to refute the idea that there are too many people in prison.

The riots of Summer 2011 showed the dangers of having so many hardened criminals at liberty. 75% of those who participated in the riots and looting had a criminal background and the average rioter had committed 15 previous offences. Even so, only one in three had been to prison and all were back on the streets to wreck havoc across the country.

But with 91,000 serious, repeat offenders being given alternative punishments to prison in a single year, it may be those riots were simply a made-for-television version of daily life for those who have to live and work among criminal thugs.

It is telling to explore what the 91,000 are doing instead of serving prison sentences.

About 28,000 received a community sentence, incapacitating them from a life of crime for a few hours a week if they show up at all. 16,000 received a mere fine and more than 7,000 were cautioned.

Statute lays down that courts may discharge offenders only in those cases were "it is inexpedient to inflict punishment". Judges found more than 15,000 such cases among serious offenders with more than 10 prior convictions.

Fully suspended sentences, once rare, accounted for another 11,000.

If the anti-prison lobby were correct, these soft sentences would reform or deter criminals - not lead to hardened criminals time and again receiving the same feeble penalties that neither punish effectively nor stop them reoffending.

By contrast, prison works - if only because while after centuries of trying humanity still knows no reliable way to reform and rehabilitate large number of serious offenders, we do know that criminals held inside prison cannot commit crimes outside. Many of his civil servants were aghast when Michael Howard tried to turn this insight into policy, but of course doubling the prison population slashed crime. America's prison-building and progress fighting crime have been even more dramatic.

Chris Grayling's announcement of a new super-prison was mocked by the same voices who mocked Michael Howard two decades ago, but they are just as wrong now as they were then. In the midst of a massive programme of deficit reduction, it is a difficult time to push for a big increase in Britain's £3.7 billion prison budget, even in light of evidence that it saves more money in crime prevention than it costs. But the first step towards a lower crime society is to look at the figures and firmly reject the dangerous fallacy that courts don't pass enough non-custodial sentences.