Overcrowded prisons will face “total gridlock in a matter of months” and run out of space in 2026 despite emergency measures to release prisoners early, MPs have warned.
A damning report from the Public Accounts Committee found a “system in crisis” was leaving many prisoners living in “inhumane conditions”, adding the previous government’s plans to create 20,000 more prison places by the mid 2020s were “completely unrealistic”.
Thousands of outstanding spaces are expected to be delivered five years late with costs spiralling to £4.2 billion – 80 per cent more than originally planned.
MPs also said the HM Prison and Probation Service (HMPPS) is operating "hand to mouth", which is detrimental to rehabilitation efforts to cut reoffending.
Chairman of the committee Sir Geoffrey Clifton-Brown said: "Lives are being put at increasing risk by the government's historic failures to increase capacity.
“Despite the recent emergency release of thousands of prisoners, the system still faces total gridlock in a matter of months."
He added that the inquiry found severely overcrowded prisons are in danger of becoming "pressure cookers" and that vital rehabilitative work is being sidelined as staff are forced to focus on controlling unsafe environments.
"Many prisoners themselves are living in simply inhumane conditions, with their health needs often overlooked,” Sir Geoffrey said.
"It is now for the government to act on the recommendations in our report if disaster is to be averted.”
The report said the adult male prison estate was at 98 to 99.7 per cent occupancy between October 2022 and August 2024, and remains "alarmingly full".
It found a quarter of prisons are doubled up in cells meant for one person and overcrowding is linked to higher rates of violence and self-harm which "increased significantly" in the year to September 2024.
The committee said fights between prisoners were up 14 per cent and attacks on staff jumped by 19 per cent in that period.
The committee also warned HMPPS was "entirely reliant" on uncertain future measures which it hopes will come from the independent sentencing review, led by David Gauke, which is expected to be published in the spring.
The MPs made similar findings of the approach taken in tackling the courts backlog earlier this month, warning the Ministry of Justice is "over-reliant" on the upcoming findings from the Leveson Review also expected in late spring.
Sir Geoffrey added: "As with our recent inquiry into court backlogs, we find a department grappling with the fallout of problems it should have predicted while awaiting the judgment of an external review before taking any truly radical corrective action."
The report said one of reasons for the shortfall of new places was that the MoJ and HMPPS assumed they could gain planning permission for new prisons in 26 weeks.
Plans to deliver the remaining 14,000 places by 2031 are "still fraught with risk and uncertainty", the committee warned.
They also said current maintenance funding of £520 million was a fraction of the £2.8 billion needed to bring the prison estate into fair condition.
Reacting to the report, prison experts warned the government cannot build its way out of the crisis.
Andrea Coomber KC from the Howard League for Penal Reform said: “It is no coincidence that violence and self-harm are at endemic levels.
"The Government has acknowledged that it cannot build our way out of this crisis. Ultimately, they must reduce demand on a system that has been asked to do too much, with too little, for too long."
She added that billions of pounds earmarked for building new prisons would be better spent on securing an "effective and responsive" probation service, working to cut crime in the community.
Richard Garside, director of the Centre for Crime and Justice Studies, said successive governments have tried – and failed – to build their way out of the prison capacity crisis.
“Rather than repeating all the mistakes of the past, the government should develop a long-term plan to contain and then reduce the prison population,” he added.
“This would allow it to close the gap between the money allocated and the costs of building, running and maintaining prisons.”
Minister for Prisons, Probation and Reducing Reoffending, Lord Timpson said: “This report exposes the catalogue of failures we inherited which almost collapsed our entire prison system. This not only risked public safety but added billions in extra costs to taxpayers.
“We have already taken immediate action to end the overcrowding chaos engulfing our jails and are now delivering on our Plan for Change to ensure prisons work, cut crime and make streets safer.
“This includes delivering 14,000 new, modern prison places by 2031 and reviewing sentencing so we never run out of space again. We’ll carefully consider the Committee’s recommendations as part of this work.”
