Prisons will be short of space for more than 12,000 criminals in three years, Whitehall’s spending watchdog has warned.
The National Audit Office (NAO) said current expansion plans were “insufficient to meet future demand”, with a projected shortage of 12,400 prison places by the end of 2027.
The plan to build 20,000 extra spaces to meet demand was so far behind schedule that it would not be achieved until 2031, five years later than promised, according to a report by the NAO published on Wednesday.
The watchdog said the delay would more than double the costs to the taxpayer of building the new jails from £4.2 billion to £10.1 billion, a rise that was equivalent to a one percentage point cut in National Insurance contributions.
The overcrowding crisis was blamed by the NAO on previous Governments’ failure to ensure tougher sentences and boosting police numbers was matched by increased space in jails.
The Ministry of Justice (MoJ) admitted to the NAO that the measures it had taken to tackle the crisis – such as the early release of prisoners – had increased the risk to public safety and of reoffending by criminals who were less likely to be rehabilitated in overcrowded jails.
Sir Geoffrey Clifton-Brown, Tory chairman of the Commons Public Accounts Committee which scrutinises Government spending, said prisons were “already at the brink” and it was “unacceptable” that plans “beset with delays” would not meet future demand.
“The MoJ has been in firefighting mode, prioritising short-term solutions to the crisis. These are not only expensive but also increase risks to prisoner, staff and public safety.
“The Government must pull together a coherent and viable long-term plan for a prison estate that meets demand and delivers value for taxpayers’ money.”
The previous Government pledged to build 20,000 new prison places by the mid-2020s but, as of September, had only created 6,518. Between 2010 and September 2024, the MoJ only added a net 1,005 prison places while the number of inmates had risen by 3,000.
The NAO said the building programme had been plagued by “overambitious” timelines and “unachievable” budgets. Two of the six new prisons took 20 months longer to get planning permission than expected. One still had not got the go ahead by October 2024.
With the prison population projected to rise by more than a fifth from the current 85,900 to more than 105,000 by November 2027, the NAO suggested the number of criminals sent to jail would outstrip the number of spaces by 12,400 by then.
The watchdog said the MoJ did not have “any contingency plans” to increase prison capacity which meant it was relying on measures such as its sentencing review to plug the gap.
The review, chaired by former justice secretary David Gauke, will consider proposals for criminals to serve their sentences on electronic tags at home under house arrest instead of jail and could see many shorter jail sentences of under a year or six months replaced by community punishments.
MoJ sources said new projections suggested the shortfall would be under half of the 12,400 due to measures already taken including the early release of prisoners 40 per cent through sentences rather than half way and a doubling in the time freed prisoners can spend on tags to a year.
“This report provides a post-mortem of the last Conservative Government, and another illustration of the dreadful inheritance they left us. Broken promises on prison building,” said a senior Labour source.
“A multi-billion cost to taxpayers. All swept under the carpet for this Government to discover on our arrival. Unlike them, we will take the decisions – however difficult – to fix prisons for good.”
The NAO report also revealed the maintenance backlog has grown from £0.9 billion to £1.8 billion. Some 23,000 occupied prison places – a quarter of the total – did not meet fire safety standards.
