Locking fewer people up results in less crime. So why are we doing the opposite?

But crime rates are not indifferent to prison policy. Locking fewer people up and investing in rehabilitation seems to reduce them. A 2007 review of over 100 studies found that non-custodial sentences – such as fines or community service – are associated with lower reoffending rates than custodial ones. The UK’s reoffending rates are high, at 26.5%, rising to 56.9% when it comes to those released after short sentences. A Ministry of Justice analysis found that community orders were more effective at reducing this risk. Studies suggest that making punishments harsher does not in itself deter crime.

So why isn’t Britain doing what works? Why are we content to spend more and get less from our justice system? It may be an issue of philosophy. Prison policies are built on two ideas. A moral one, which holds that those who have sinned should be punished, and a practical one: prisons should reduce crime, either through deterrence or rehabilitation.

Britain, like other Anglophone countries, leans more heavily towards the first, while western and northern Europe are more practical and evidence-based in their approach. Polling in England and Wales consistently finds the public does not believe sentences are long or harsh enough; politicians are wary of flouting this strongly held opinion, even when evidence and economics points the other way. This state of affairs received a particular boost during the “tough on crime” policies between 1992 and 2010: the narrative drove public opinion, which in turn drove harsher sentences. It may be, too, that the reactive nature of Britain’s adversarial politics lends itself to sentence inflation: politicians want to respond quickly to tragic events, and harsher punishment is a relatively simple way of doing so.

The structure of the press likely contributes too: a recent justice committee report found that the British media skews perception of crime with a particular focus on “atypical” cases, which it presents with powerful headlines and strong terminology. Public campaigns from victims of crime, meanwhile, tend to find sympathetic coverage, and command influence: mandatory minimum sentences were a result of such campaigning.

But it may be that public opinion is more malleable than politicians think. Education may alter it: many of us have an incomplete understanding of how the justice system works. A report by the Office for National Statistics (ONS) found that most people thought crime across the country had been rising in the very period in which it had been falling off a cliff. Polling by the justice committee found that a majority believed that sentences were getting shorter, despite the fact they were growing. Studies suggest giving people more information about sentencing guidelines softens their stance.

Polling also suggests a divide in opinion between violent and non-violent crime. Most think antisocial behaviour, petty theft, harassment, vandalism and carrying or consuming illegal drugs should not carry a prison sentence. When presented with trade-offs, 58% thought sentences should be increased for violent crimes, but just 32% felt they should be stricter for non-violent crimes.

Keir Starmer is attempting to turn the tide, shortening sentences and putting a greater emphasis on rehabilitation. Yet the prison population is set to soar: £2.3bn has been earmarked to build more prisons over the next two years. There is room to be bolder, especially when it comes to keeping non-violent offenders out of prison.

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