MPs criticise 10-year deal struck in ‘blind panic’ to rent Dartmoor prison, where high levels of radon had been detected

A “catastrophic” decision by the Ministry of Justice to sign a 10-year lease on a prison where high levels of a poisonous gas had been detected is expected to cost the UK taxpayer more than £100m, parliament’s spending watchdog has concluded.

The public accounts committee said the 2022 deal to rent HMP Dartmoor from the Duchy of Cornwall was signed “in a blind panic” by senior civil servants looking to guarantee prison places.

The category C prison, which held many sex offenders, was closed in 2024 after levels of radon up to 10 times higher than the recommended limit were recorded in some areas. The government has since admitted that it was aware that “elevated readings” of the gas were found in 2020.

Radon, a colourless and odourless radioactive gas, causes about 1,100 lung cancer deaths in the UK every year, according to the Health Security Agency.