The Ministry of Justice’s decision to sign a 10-year lease on HMP Dartmoor, despite known high levels of radon gas, is set to cost UK taxpayers more than £100 million, according to the public accounts committee. The committee described the 2022 deal as a ‘catastrophic failure’ and said it was struck ‘in a blind panic’ to secure prison places.
The category C prison, which held many sex offenders, was closed in 2024 after radon levels up to ten times the recommended limit were detected. Radon, a colourless and odourless radioactive gas, causes about 1,100 lung cancer deaths annually in the UK. The government admitted it was aware of elevated readings as early as 2020.
Under the lease, the Ministry of Justice cannot terminate until December 2033, and currently pays around £4 million per year for the unusable prison, including rent, business rates, and security. An additional £68 million is expected for fabric improvements over the lease period. The Duchy of Cornwall, which provides income for Prince William, owns the prison.
Geoffrey Clifton-Brown, Conservative chair of the committee, said the handling was ‘an absolute disgrace, from top to bottom’. He rejected the MoJ’s excuse that the deal was driven by the need for prison places. More than 500 former inmates and staff are bringing legal claims over health risks from radon.
The Ministry of Justice defended the decision, stating it was taken when prisons were on the ‘brink of collapse’. In October, permanent secretary Jo Farrar said it was a ‘sensible and pragmatic decision’ given the information available at the time. The Health and Safety Executive’s investigation into radon at the prison is ongoing.
