Britain’s prison overcrowding crisis is driven by sentence inflation, not crime

The prisons in England and Wales are full, and successive governments have struggled to increase capacity as the numbers of prisoners rise.

The prison population is determined by the type and length of sentence, the regimes in place for release from custody, and the recall of prisoners for breach of licence conditions. All these factors need attention because of the impossibility of expanding capacity to keep up with demand.

There has been a striking rise in the use of custodial sentences since 1993. In 1993, 16 per cent of sentences were immediate custody, but this rose to 32 per cent in 2024. This has been accompanied by a reduction in the use of community and suspended sentences.

Along with the increased use of immediate custody, sentence lengths have increased.

The average sentence length in 1993 for an offence that could only be tried in the crown court was 16 months. In September 2025, it stood at 22 months. Sentences of upwards of 10 years more than tripled between 2010 and 2024. Shorter custodial sentences (12 months or less) decreased by 64 per cent. Prisoners serving life sentences have increased from a little over 3,000 in 1993 to just over 7,500, and the minimum terms they must serve have increased.

These increases have been driven by statutory interventions by successive governments to increase sentences, introduce minimum sentences, and significantly extend the time life-sentence prisoners must serve before they can be considered for release. This has driven up sentences across the board.

The rate of incarceration in England and Wales, steadily increasing over the last 25 years, is high by European standards at 138 per 100,000. By contrast, in France it is 126, Sweden 92, Germany 71, and the other Nordic countries even less.

The time spent in custody by many prisoners has increased. Most do not serve the whole of the headline sentence and are released automatically at some stage. Others are released only if the Parole Board considers it safe to do so. Release provisions are complex and ever-changing. The Independent Sentencing Review recommended a simpler model which, subject to good behaviour, would release determinate-sentence prisoners after a third, which parliament has included in the Sentencing Act 2026.

Sentencing is not only about punishment. The statutory purposes of adult sentencing also include the reduction of crime, the reform and rehabilitation of offenders, the protection of the public, and reparation. There is no hierarchy, and imprisonment is not the only tool of punishment available to the court. But if there is to be prison, the court must not pass a custodial sentence unless nothing else will do, and it must be for the shortest term commensurate with the seriousness of the offence.

All politicians acknowledge the crisis in our prisons, yet there has been little public acknowledgement that sentence inflation has been a potent driver of an increasing prison population, nor of whether it aids rehabilitation and reduction of crime.

There are about 85,000 prisoners in our prisons. About 20 per cent of those are on remand awaiting trial or sentence, and 14 per cent have been recalled for breach of licence conditions after release.

In 1993, the prison population was around 44,000, and of recalled prisoners, fewer than 100.

The Sentencing Review found that between 2010 and 2024, sentence increases appeared to be driven by an increase in the custody rate and the length of custodial sentences rather than changes in the mix of crime. These trends flow from legislative and policy changes, which reflect political judgements about public mood.

But that public mood is not evidence-driven. There is a widespread view that serious crime has been rising and that sentences have been falling. Neither is correct.

The Office for National Statistics (ONS) has noted a long-term decline in common types of crime since the 1990s. Homicide offences are at the lowest ever recorded, and offences of serious violence have been falling. But, according to the ONS, public perception has been that crime was rising. In 2023, the Justice Select Committee found that most people surveyed believed that sentences were shorter than they were 25 years ago. The opposite is true.

The fall in serious offending has been seen across advanced democracies. Academic research does not suggest that increased sentencing is a factor. Research for the Sentencing Council in 2022 found that there was little evidence that increasing sentences had a deterrent effect. The Council pointed to the reality that much offending is associated with an absence of rational thinking, with emotional arousal, and the influence of drink or drugs.

Governments appear to have been legislating based on myths rather than reality.

Sentence inflation has contributed to overcrowding in our prisons. That, in turn, has resulted in poor conditions for those incarcerated and for prison staff. Necessary work on rehabilitation, training and education is not being undertaken. Yet it is through such work that reoffending is reduced and prisoners are encouraged to become productive members of society.

Criminal activity has a clear economic cost, and keeping people in prison is expensive.

The average annual cost per prisoner is a little under £55,000. The government has announced spending of £4.7bn to build prisons between 2026 and 2030. There is a £1.8bn maintenance backlog in prisons, leaving aside necessary upgrades. The Ministry of Justice gives an overall figure of between £9.4bn and £10.1bn over 10 years for capital spend on prisons.

The costs of reoffending were estimated at £18bn a year by the House of Lords Justice and Home Affairs Committee in 2025.

Imprisonment is very expensive, but expenditure on effective rehabilitation is money well spent. The average cost to the Probation Service in 2023-2024 of an additional person on their caseload was estimated at £3,150.

Overcrowding has led to direct adverse consequences for many prisoners. The Prison Service itself accepts that in the 12 months to March 2025, 25 per cent of prisoners were held in overcrowded conditions, which did not provide a decent standard of accommodation.

The Justice Committee in 2025 found that 50 per cent of prisoners are not taking part in education or work in prison, and two-thirds of offenders are not in education or work six months after release. Eighty per cent of all offending in England and Wales is reoffending. Overcrowding has led to arbitrary prisoner transfers, disrupted sentence progression, and reduced access to purposeful activity, education and family contact.

A failure to take steps to rehabilitate prisoners will do nothing to reduce reoffending rates and reduce crime. Indeed, it is likely that poor prison conditions, including overcrowding resulting from sentence inflation, have the opposite effect.

A custodial sentence is a serious punishment, and the longer the sentence, the greater the punishment. The public is protected while a prisoner is inside, and individuals targeted by offenders gain respite. Sentences for those considered dangerous provide extended protection and are needed. But that is not most prisoners. It is well understood that longer sentences have little deterrent effect. It is the certainty of punishment rather than its length that matters. Rehabilitative interventions during the sentence and support after release are more important than sentence length in reducing reoffending. Indeed, there is good evidence that longer sentences increase the likelihood of reoffending for some offenders.

The Sentencing Review looked at programmes in Texas, the Netherlands and Spain, all of which reduced reliance on custody, increased programmes focused on rehabilitation, and saw reductions in the prison population and reoffending.

In England and Wales, we seem to have achieved the worst of all worlds. Sentences have increased along with the proportion of the sentence many offenders serve in custody. Prisoners have been more readily recalled to prison. All of this inflicts greater punishment but comes at great cost. There are growing costs to fund the prison population, and there are human costs borne by prisoners, their families and Prison Service staff. And there are wider costs, which result from the adverse impact on rehabilitation and reoffending. In short, lengthening a sentence or the time spent in custody will often be counterproductive.

The Sentencing Act 2026 marks the first reversal of a longstanding legislative trend. It will see many offenders released after serving a third of their sentences, restrict the use of short custodial sentences, and widen the availability of suspended sentences. It also seeks to tackle the overuse of recall.

It was perhaps inevitable that the recent legislative reforms were presented as a necessary reaction to overcrowding in prisons rather than being, in themselves, the right thing to do.

One of the recommendations of the Sentencing Review was to establish an external advisory body on sentencing policy, which would be informed by evidence on what works to reduce crime and prevent reoffending. It would analyse the likely effects of policy changes and make longer-term assessments of the impact of policy. The Justice Committee has made a similar recommendation. Sentencing policy and legislative reform in recent decades have not been grounded in evidence of their effect on crime or reoffending. Raw politics cannot be taken out of this area altogether, but it would be a welcome change if our major political parties could move away from reacting to events to a more principled and evidence-based approach. Perhaps then the pressures that have produced sentence inflation would abate, and we may end up with sentencing that does not, in some respects, do active damage to the public interest.

Lord Burnett of Maldon was Lord Chief Justice of England and Wales 2017 to 2023 and a member of the Independent Sentencing Review. This is a summary of parts of the Sir Patrick Neill law lecture given by Lord Burnett on 20 February 2026 at All Souls College, Oxford