Adam, an inmate at HMP Dartmoor, first noticed something was wrong when he saw neon-yellow signs being put up around the prison.
The “do not enter” signs indicated the presence of radon gas – a dangerous and toxic radioactive substance linked to increased risk of lung cancer.
Staff were reassuring and said it could be contained. But monitors soon started being fitted in every cell and in communal areas, like the kitchen, where Adam worked seven days a week.
Some six months later, in December 2023, dozens of prisoners in F wing – which housed those vulnerable due to their age and ill health – were suddenly moved out.
And over the next few months, the headcount would go from around 650 prisoners to just over 100 after government officials decided that radon exposure levels were too high. By August 2024, the last remaining prisoners had been evacuated.
Adam, who had been moved out in January 2024 to Stafford, was one of those who received a personal letter titled “Exposure to Radon” from His Majesty’s Prison and Probation Service (HMPPS). A radiation protection advisor had assessed that Adam had been exposed to five times the annual safe limit of radon gas, the letter said. He was also warned he may experience loss of appetite, unexplained weight loss, breathlessness or coughing up phlegm with blood in it.
Officials ‘knew it was dangerous and couldn’t care less’
Adam, not his real name, is now one of around 750 former inmates and staff who have joined a class action lawsuit against the Ministry of Justice (MoJ), seeking at least £60,000 each in compensation for being put at risk. Nearly 100 claims have been submitted so far.
Among them is a former NHS staff member who believes his exposure to radon at Dartmoor has caused an unexplained drop in his fertility. There is also a former senior prison officer who worked at the site for 18 years but left after completely losing trust in HMPPS due to the “lies” told about radon. And there are former prisoners crippled by health anxiety who fear their health problems are linked to the gas.
Lawyers said they have also been approached by three families of people who died after spending time at Dartmoor, including one prisoner and two officers.
Former inmates have now told The Independent of their anger at being sent to the Category C men’s jail as the government scrambled to find cells during a growing national overcrowding crisis, despite chiefs previously being alerted to unsafe radon levels.
The ageing Victorian prison, owned by Prince William’s Duchy of Cornwall, is built on granite bedrock, which can emit the naturally occurring radioactive gas.
The Health and Safety Executive (HSE) has launched a criminal investigation into how prison leaders handled the radon scare following claims they may not have evacuated quickly enough.
The HSE’s completed report is with their legal department for review, but the outcome, which could include criminal charges or censure by the body, is yet to be published.
Mladen Kesar, solicitor at Kesar and Co, who is leading the legal action, said: “This is about putting humans in a dangerous situation where the public authority knew it was dangerous and couldn’t care less whether that had any consequences for their health, including for their own staff.”
The claims, which are dependent on ongoing legal aid funding to get to court, threaten to expose a litany of failings in how the MoJ handled the environmental crisis. Mr Kesar and his team say the government knowingly put hundreds of prisoners and staff at risk – gambling with their health in a scramble for space.
Shockingly, the government is still paying around £4m a year for the unusable prison after officials signed a £100m 25-year lease in 2022, despite measurements from 2020 showing the prison had unacceptably high levels of radon.
Under the terms of the lease, taxpayers must also foot the bill for £68m worth of improvements to the unusable site, and officials have splashed a further £1.2m on radon mitigation efforts. The lease has a break clause that allows the MoJ to exit Dartmoor at any time after December 2033, having given five years’ notice.
The fiasco has been slammed by the government’s public spending watchdog as a “catastrophic failure”, while civil servants desperate for prison space have been accused of acting in a “blind panic”.
Antonia Romeo, who was recently appointed by Sir Keir Starmer as the new cabinet secretary, was the most senior civil servant in the MoJ at the time. Gary Badley, the civil servant who the MoJ named as the person responsible for lease negotiations, was subsequently put in charge of renovations and maintenance for the whole prison estate.
Radon is a colourless, odourless natural gas, formed when small amounts of uranium in rocks and soils decay.
It can build up in indoor areas and, while it can be controlled through ventilation, it is known to increase a person’s risk of lung cancer, with more than 1,100 deaths from the disease attributed to radon each year in the UK, according to the UK Health Security Agency (UKHSA).
According to Sir Geoffrey Clifton-Brown, the chair of the public accounts committee, the decision to evacuate prisoners from Dartmoor only came after the health watchdog “more or less told” the government to move people out because the radon levels breached health and safety regulations.
Now the MoJ is carrying out 42 investigations at sites across the prison and probation estate, including at 15 other prisons.
Staff told not to worry about ‘minimal’ exposure
One male former NHS worker, who worked in prisons for five years, first heard about radon when detectors were installed in his office in 2023.
“There was no formal notification via anyone, really,” he said. He remembered a full staff address in early 2024 by lead prison governor Steve Mead, just after the new lease with the Duchy had come into effect. It was made clear there wasn’t a plan to close the prison, but that mitigation measures were due to be put in place.
“We were repeatedly told we were only exposed to ‘flash exposure’ – emphasising that it was minimal,” he said. “Findings have since shown that this was wholly untrue.”
Some staff felt the governor was trying to be as transparent as possible with the little information he was given. Others said they were kept in the dark.
The process of shutting parts of the prison was described as “ad-hoc” and “all over the place”, as site safety teams experimented with how they could lower the levels of toxic gas.
A “mammoth task” was then undertaken to assess the radon exposure risk for each prisoner and identify who needed to be moved out first. Former staff described the governors as being “completely overwhelmed” by the process.
‘My blood tests look similar to those sterilised by radiation in mines’
While working at Dartmoor, the former member of NHS staff said he experienced an unexplained drop in his fertility. Over the course of three tests from 2021 to 2023, despite fathering children before, his fertility started to decline. “At that time, everything was normal, we had a full sexual health screening. Everyone else was all cleared. All they could tell was that it was my fertility that was the issue.”
He has since done his own research into the potential effect of radon gas on fertility, and he believes his blood test results are similar to those of people who have been sterilised by radiation from working in mines.
He said: “There is always that niggling doubt now. If I’ve been exposed to levels of radiation that have likely sterilised me, that would indicate that I’ve been exposed to levels of radiation that will lead to other medical complications in the future as well.”
Fears ‘laughed off and decried’
Mark McKay, a former prison officer who served at HMP Dartmoor for nearly 10 years, said there had been an “irretrievable breakdown of trust” between him and HMPPS over radon.
He remembered that, in 2013, staff had been told the jail had been given a 10-year notice to close. When the lease extension was signed in 2022, it was like a “stay of execution”, Mr McKay said, adding: “I believe that prompted them to do all of the stuff they had neglected to do in that 10-year period, believing the jail would be closed in 2023.”
Mr McKay, who was the health and safety representative for the Prison Officers Association (POA), said when extremely high radon readings were recorded in the kitchen, he was told this was due to water in an irrigation tunnel under the kitchen. Officials thought that, if this was drained, the readings would improve, but this didn’t happen, he said.
“When I challenged the health and safety manager, she basically said it was nothing to worry about,” Mr McKay said.
He said that, when he suggested that prison chiefs do additional readings to get an idea of radon exposure across the whole prison, he was “laughed off and decried”.
When prisoners were being moved out, Mr McKay recalled one of the governors referring to a prisoner in A wing. “They said ‘Oh, he’s got to go because we’ve cooked him’, meaning he exceeded his annual exposure level in a matter of days if not weeks.”
Radon ‘first detected in 2007’ but staff were kept in the dark
Radon monitoring at Dartmoor goes as far back as 2007, with some readings from that time found to “exceed the threshold at which the regulations apply”, according to a letter unearthed by the BBC.
Another former prison officer, Robert Barnett, transferred from The Mount to Dartmoor that year. He was there for 10 years and said there was never any mention of the deadly gas.
Now retired and aged 76, a CT scan recently discovered a growth in his lung. It was initially thought to be linked to his contact with a prisoner with tuberculosis in 2013, but tests have ruled it out. Although the cause is uncertain, he fears it could be linked to radon.
Former prisoner Kieran, 31, believes he stayed in cells in some of the areas with the highest readings during his 13 months in Dartmoor.
He said: “It’s under-appreciated that there aren’t any formal tests to see if you have been exposed [to Radon] and what damage has been done. But just the pure fact that it has been linked to lung cancer, that’s the huge concern for me and my family.”
He explained that during his time at Dartmoor from October 2021 to November 2022, his breathing got considerably worse.
“I never had breathing difficulties [previously],” he said. “[Now] I wheeze a lot more. I struggle with my breathing – even walking up a hill, it completely takes it out of me. It’s such a struggle.”
Conditions in the historic prison were “horrendous”, he said, with cramped cells heated only by a pipe in the floor and limited ventilation.
While some prisoners have received letters explaining their radon exposure, many haven’t, including Kieran.
‘It’ll be fine, chuck them in’
Another prisoner at Dartmoor from September 2021 to January 2023 said he is furious he has been put at risk.
“The only inkling we had that there was something wrong was when they started putting alarms in cells,” he told The Independent. “We were asking ‘What are these alarms for?’ But they weren’t alarms, they were radon detectors.”
The inmate, who was held on B-wing, fears his exposure could have been heightened by Covid-19 restrictions, which meant he spent even longer locked in his cell each day.
He said: “There’s evidence to suggest that the MoJ and relevant authorities were fully aware of the dangerous levels of radon exposure in Dartmoor. And they thought, ‘do you know what, we are the MoJ and we need prison spaces – it’ll be fine, chuck them in.’”
He added: “It’s very frustrating to know that they deliberately and wilfully put me in harm’s way with high levels of a dangerous gas.”
‘Doing the hokey cokey’ with prisoners
By December 2023, F and E wings were closed and prisoners were transferred out, but the evacuations were paused in May 2024. In the first week of July, the decision was taken to move men back into the prison over the next few months, with up to 30 prisoners a week coming in.
In a further twist on 17 July, with radon readings on the wing atriums very high, the decision was taken to move everyone out – and by the beginning of August, the prison had no inmates.
One prison officer described the process as “doing the hokey cokey” with prisoners. Such was the chaotic decision-making that some inmates were moved in for two weeks before they had to be moved out again, one source said.
Some of the prisoners were old and frail, needing help to get in and out of cells, and so would have been spending large amounts of time locked in with high levels of radon.
While prisons minister James Timpson has told MPs that a decision on the future of Dartmoor is yet to be made, insiders said the site has been stripped, locks removed from cell doors and gas cut off to the empty wings.
A private firm, Sentinel Group Security, took over the prison security last month, tasked with guarding the site from intruders. New security cameras and better wifi have apparently been installed to assist the contractors.
A spokesperson for the company said they had been contracted to provide security services for an initial period of a year, but anticipated this could be extended. They said they had completed their own radon inspection and risk assessment to keep their employees safe.
A HMPPS spokesperson said: “We continue to assess safety and feasibility at HMP Dartmoor, and will make a decision on the site in due course.
“As there is an ongoing HSE investigation and live legal proceedings, it would be inappropriate to comment further. But we have strengthened radon management across the prison estate in line with regulatory requirements .”
