GRAVE concerns hang over the future of Dartmoor Prison which is being temporarily closed because of “dangerously high” radon levels.

Local councillors say it is an exceptionally worrying time for the 276 staff and the community who have been “left in the dark” over what is happening.

More than 400 prisoners were removed from the Princetown jail after a Health and Safety Executive (HSE) investigation last December found radon levels 10 times the recommended workplace limit.

The remaining 175 convicts will move to other prisons by the end of this month and the site closed.

A spokesperson for the Ministry of Justice said: “Public safety will always be this government’s priority.”

Prison officers are being deployed to other prisons in the region.

It is another blow for the Napoleonic prison which was earmarked for closure in 2013, before being reprieved in 2019 because of escalating prison numbers nationally.

The Ministry of Justice’s lease with the Duchy of Cornwall, which owns the building and land, runs until 2048, with a break clause in 2033.

The closure could be for up to two years, and comes at a time when almost all cells across the country are full, leading the government to release some prisoners after they have served 40 per cent of their sentence, rather than the usual 50 per cent.

The ministry said it was confident the prison system could manage, but any further events like this at Dartmoor would be harder for the system to withstand.

Devon County councillor Philip Sanders (Con, Yelverton Rural) said: “It is an exceptionally worrying time. I think everyone is nervous and not sure what is going to happen. We can only wait and see, there is no clear information, and the cost of dealing with radon could be very significant.”

Radon is an odourless radioactive gas formed by decaying uranium found in rocks and soils, particularly granite which is common on Dartmoor.

“We have lived with radon for many years and anyone in this area with an older property will have radon levels in their house or business,” said the councillor.

“It is nothing new and I don’t think there is any evidence that the prison officers who served at Dartmoor 100 years ago were adversely affected, but the levels of radon are considered no longer safe and it’s no longer acceptable.”

Cllr Sanders said coachloads of people come to see the 215-year-old listed iconic prison and spend money in local businesses, so if it closes permanently it would be “quite serious” to the community and to the staff who work there.

“This is a problem we faced two or three years ago and our local MP Sir Geoffrey Cox was very good at actually dealing with that at the time and managed to keep it open.

“The problem is dealing with radon can be very expensive, so for the Ministry of Justice to have to face up to all those changes might persuade them that they should keep the prison closed.”

The government said it would take further advice from specialists and keep staff updated.

“We are continually keeping the position at Dartmoor under review and work is underway on the development of permanent mitigations,” the MoJ said.

“We are working with staff to ensure they are supported and safely placed in alternative roles.”

It added that the new government would be setting out its long-term plans to address prison capacity later this year.

Torridge and Tavistock MP Sir Geoffrey Cox said mitigation measures had already begun under the previous government as the radon problem had been known about for several years.

He said he was puzzled why it is being temporarily closed now given the shortage of prison places.

He has written to the secretary of state for justice Shabana Mahmood questioning why the decision has been taken.

Sir Geoffrey said: “When I visited last year, I found a well-run prison and dedicated staff. It makes no sense at all for this prison to be closed without the most compelling reasons and it is vital for the staff and their families that the uncertainty is removed soon.”

Princetown postmaster and deputy leader of West Devon Borough Council Cllr Mark Renders (Ind, Dartmoor Forest) said he hoped that Dartmoor would remain a prison for many years, but if it closes there are several possibilities for it.

“I would think it could be a big outward-bound site aimed at the youth, with guides or scout movements staying there. They camp a lot on Dartmoor anyway. Wouldn’t it be great to come and stay a night in a haunted cell?

“It is a big site and it could be used for some affordable housing which we are in desperately in need of. We have a housing crisis and that was recognised in the King’s Speech as something the government was going to concentrate on nationally. But that is one for the Duchy, not me, hopefully it does not close but maybe it’s just an idea to chuck in the pot.”

He said 20 years ago, the majority of people employed at HMP Dartmoor lived in the community but now the majority came from outside Princetown.

“It does not mean that any closure wouldn’t have a big impact on the village,” he added. “We know very little about what is happening, everyone has been left in the dark”.

The Prison Officers’ Association said it had been informed that there are “dangerously high levels” of radon on the landings at the prison but it had not been told how long it would take for mitigations to be put in place.

“The POA is updated on a regular basis regarding mitigations and the effectiveness of these,” it said.

The Duchy of Cornwall said it is working with the Ministry of Justice throughout this process.

By Alison Stephenson