Prisons Don’t Work. So Why Are We Building More?

The UK government is spending billions on expanding the prison system, despite clear evidence that incarceration fails to reduce crime or rehabilitate offenders. With plans to create 20,000 new prison places by 2031, the cost of this expansion is projected to reach at least £10.1 billion, overshooting its initial budget by more than £4.2 billion.

This staggering expenditure comes at a time when public services are underfunded, crime prevention measures are neglected, and the Probation Service—once a vital alternative to custodial sentences—has been downgraded to breaking point. If the goal is a safer society, why is the UK funnelling billions into a failing system rather than addressing the root causes of crime?

The Cost of Prisons vs. Their Effectiveness

Prisons are not working as intended. The UK has one of the highest reoffending rates in Western Europe, with 25.1% of adult offenders committing another crime within a year of release. Among those serving sentences under 12 months, the reoffending rate soars to over 50%. Rather than rehabilitating individuals, the prison system often worsens their prospects, increasing their chances of returning to crime.

At present, the prison population in England and Wales is around 88,350, barely below its operational capacity of 89,543. Overcrowding is rife, with prisons struggling to provide meaningful education, training, or rehabilitation. Instead of creating pathways to reintegration, these conditions breed further criminality.

Countries with lower incarceration rates tend to have lower reoffending rates. For example, Norway has an incarceration rate of 72 per 100,000 people and a reoffending rate of around 20%. The emphasis in Norway is on rehabilitation and reintegration into society, with prisons designed more like open campuses that provide education, job training, and therapy.

The Downgrading of the Probation Service

In 2014, the UK government privatised much of the Probation Service, fragmenting what had once been an effective system for managing offenders outside of prison. The disastrous part-privatisation led to a rise in reoffending and worsened the quality of offender supervision. By 2021, the government was forced to renationalise the service, but the damage had already been done.

Despite this, probation remains underfunded and overstretched, with reports highlighting unmanageable caseloads, staff shortages, and a failure to properly supervise high-risk offenders. A fully functioning Probation Service would allow more non-violent offenders to be managed in the community, avoiding costly and unnecessary prison sentences. Instead, the government is doubling down on mass incarceration.

The Alternative: Investing in Prevention, Not Punishment

If the UK truly wants to reduce crime, investing in rehabilitation, mental health treatment, and addiction services would be far more effective than expanding prisons. At least 60% of prisoners have a history of drug misuse, and over 70% of female prisoners suffer from two or more mental health conditions. Many offenders would benefit far more from targeted treatment than from a custodial sentence.

In addition, homelessness and unemployment are significant factors contributing to criminal behavior. Around 25% of the prison population were homeless before incarceration, and prisoners are 13 times more likely to be unemployed than the general population upon release. Addressing these social issues could significantly reduce the need for incarceration.

For the £3 billion the government is committing annually to expanding the prison estate, it could:

• Fully restore and expand probation services to reduce reoffending rates.
• Fund drug and alcohol treatment programs to help offenders break the cycle of addiction-driven crime.
• Expand mental health services, reducing the number of vulnerable individuals ending up in prison.
• Develop community-based sentences, keeping non-violent offenders out of overcrowded prisons while addressing the root causes of their behaviour.

More Prisons, More Costs—With No Benefit to Society

Keir Starmer’s government is also considering “peacekeeping” missions in Ukraine, which would come at further expense to UK taxpayers, diverting even more resources away from home. With stretched public finances, it is indefensible to pour billions into prisons that don’t work while underfunding services that could prevent crime in the first place.

A study by the Ministry of Justice in 2013 found that community sentences were more effective at reducing reoffending rates than short-term prison sentences. Offenders who served community sentences were 8.3% less likely to reoffend within a year compared to those who served prison sentences.

It is time to rethink our approach. Instead of expanding a failing system, the UK should be investing in prevention, rehabilitation, and alternatives to incarceration. The evidence is clear: prisons don’t work—but properly funded services do.

By Pat Harrington

Picture credit

By Derek Harper, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=13742139