PLANS to boost prison capacity could fall short by thousands of cell spaces and cost taxpayers billions more than anticipated, Whitehall’s spending watchdog has warned.

The National Audit Office (NAO) said the government’s current expansion plans are “insufficient to meet future demand.”

The overcrowding crisis stems from the previous Conservative government’s failure to ensure longer jail sentences and increased police numbers aligned with available prison space, according to its report published today.

The watchdog said that the government’s 2021 pledge to create additional cell spaces through new prisons, temporary wings and refurbishments is now delayed until 2031, around five years later than promised.

The report comes ahead of fresh prison population projections due to be published by the Ministry of Justice (MoJ) tomorrow.

Prison Reform Trust chief executive Pia Sinha described the findings as “damning” and said they laid bare the “negligence of previous governments and their approach to penal policy” which has left taxpayers facing an “eye-watering bill with no certainty on when the ongoing prison capacity crisis will end.”

“Politicians have been dishonest with the public — promising to lock people up for longer but failing to provide the prison places necessary or being upfront about the costs of doing so. This cannot continue,” she said, calling for “bold proposals” in the sentencing review.

Howard League for Penal Reform chief executive Andrea Coomber said the “scathing” report confirms “we cannot build our way out of the prison capacity crisis.”

She added: “We have to reduce demand on a system that has been asked to do too much, with too little, for too long.”

Prison Officers Association national chairman Mark Fairhurst said total mismanagement of the service has “left us in a position that will inevitably lead to an increased burden on the taxpayer.”

He said: “The solution is not to waste money on building more prisons but to invest in the modernisation of the prison estate, creating more secure mental health beds in our communities and ensuring robust community sentences supervised by professional probation staff meet the needs of the public.”

Centre for Crime and Justice Studies director Richard Garside blamed governments and parliament for being “joint architects of a decade-in-the-making prisons crisis” as he called on ministers to “set a fresh course, aimed at containing prison population growth in the short-term and reducing it in the medium to long-term.”[online ends]

The MoJ was contacted for comment.