SPENDING £4 million a year to keep open an unusable jail is an “embarrassing sign” of the state of prison management, campaigners said today.

Prison reform groups slammed the government after a report from the parliamentary spending watchdog revealed the Ministry of Justice agreed to a 10-year lease at HMP Dartmoor despite high levels of poisonous gas at the site.

The public accounts committee said the deal signed in 2022 to rent the prison from the Duchy of Cornwall was concluded “in a blind panic” as civil servants looked to increase the number of places for prisoners.

The report found that HM Prison and Probation Service (HMPPS) locked itself into the deal until December 2033, despite it being shut in August 2024.

Radon, a radioactive gas which can cause lung cancer, was found at 10 times the safe level of concentration in some areas of the prison as early as 2020.

Andrew Neilson, campaigns director at the Howard League for Penal Reform, told the Morning Star: “That the government is spending £4m a year to keep open a jail it can’t use is an embarrassing sign of how disastrous the prison capacity crisis has become.

“Rather than continuing to focus on increasing prison places, the government must urgently address the inadequacy of the prison cells it already has and look to significantly reduce population numbers so it can begin providing safe, productive sentences for the people held in our jails.”

Public accounts committee chair Sir Geoffrey Clifton-Brown called the ministry’s handling of the lease of Dartmoor Prison an “absolute disgrace, from top to bottom.”

Its report found that £1.5m of the estimated £4m yearly cost of the now defunct prison would go to the royal family.

The lease obliges HMPPS to pay annual rent of £1.5m to the Duchy of Cornwall, which is part of the private assets of the Prince of Wales.

Prison upkeep including security and additional business rates make up the rest of the £4m yearly bill. The lease also obliges the HMPPS to make improvements to the site, which cost a total of about £68m.