To ask the Secretary of State for Justice, what estimate he has made of the cost of tackling radon gas at Dartmoor Prison.

HMP Dartmoor is an historic prison, constructed in 1809 which received Grade 2 heritage listing in 1987, and so is a complex suite of buildings that need to be fully understood to ensure any mitigation action taken to manage the presence of radon gas will be effective.

It is important to ensure the correct investigations are undertaken now, so the solutions developed are the most effective and best value option, whilst ensuring the custodial capacity is optimised in a safe and secure manner. It would be remiss to implement solutions without ensuring they are effective. It is anticipated that a costed programme will be available later this year.