What Is Dartmoor Prison Like? History, Radon Closure and What Happens Next
Last reviewed: July 2026
Dartmoor is probably the most famous prison in England: a granite fortress on a bleak moor that has appeared in countless films and novels. But the reality in 2026 is very different from the myth. This page explains what Dartmoor was like as a working prison, why it closed, what has happened since, and what families and former prisoners need to know now.
Key facts about HMP Dartmoor
| Fact | Detail |
|---|---|
| Status | Temporarily closed since summer 2024; future under review |
| Location | Princetown, Dartmoor, Devon PL20 6RR |
| Role before closure | Category C training prison for adult men |
| Opened | 1809, originally for prisoners of the Napoleonic Wars |
| Reason for closure | High levels of radon, a naturally occurring radioactive gas |
| Prisoners moved | Population transferred to other prisons by August 2024 |
Why did Dartmoor prison close?
Radon is a colourless, odourless radioactive gas that seeps out of granite. Dartmoor sits on some of the most radon-prone geology in Britain. Monitoring found levels in parts of the prison well above safe workplace limits, and after initial attempts to manage the problem, the decision was taken in 2024 to move everyone out. Around 175 men still held there were transferred, and the site has been closed to prisoners since. In 2026 the Health and Safety Executive took the rare step of a Crown censure over historic radon exposure at the jail; we cover that in detail in our page on the HSE Crown censure over radon at HMP Dartmoor.
Will Dartmoor reopen?
That is genuinely undecided. Ministers have said the closure is temporary and that reopening depends on whether the radon can be engineered out at a reasonable cost, with funding tied to government spending decisions. The Independent Monitoring Board has publicly pressed for an urgent decision about the site’s future, and the POA union has planned on the basis of a closure lasting about three years from 2024. Given the pressure on prison places in England and Wales, the Ministry of Justice has an incentive to recover the roughly 640 places Dartmoor offered, but no reopening date has been announced. Treat any date you see quoted online with caution.
What was Dartmoor like as a working prison?
Before closure, Dartmoor was a Category C training prison, meaning most men there were in the later part of their sentence and working towards release. Its Victorian wings were cold and austere, but the prison was known for workshops, farms in earlier eras, and a comparatively settled population. Its isolation was the biggest complaint from families: Princetown is a long, slow journey from anywhere, and winter weather on the moor could make visits an ordeal. The site also houses the Dartmoor Prison Museum, which remains a popular visitor attraction and tells the story of the jail from 1809 onwards.
This site’s founder, Daniel Hockey, served a prison sentence himself, moving from HMP Wandsworth through to open conditions at HMP Ford, and wrote about the experience in The Secret Prisoner (2021). His experience of the difference between a harsh Victorian jail and a working training prison shapes how we describe places like Dartmoor; you can read more about Daniel here.
1. Believing Dartmoor still holds prisoners. It has been empty since 2024.
2. Confusing the prison with the museum. The museum is open to the public; the prison itself is not.
3. Thinking Dartmoor was a maximum-security jail in modern times. It last operated as a lower-security Category C training prison, not Category A.
4. Trying to book a visit there. There is nobody to visit; use GOV.UK to find where a prisoner was moved.
5. Assuming radon risk means former prisoners or visitors were certainly harmed. Radon risk builds with long-term exposure; anyone worried should speak to their GP.
Frequently asked questions
Where were Dartmoor’s prisoners moved to?
They were dispersed to other prisons across the South West and beyond according to space and security category. Families were notified individually; the find a prisoner service is the reliable way to confirm a location.
Who owns Dartmoor prison?
The site is owned by the Duchy of Cornwall and leased to the Ministry of Justice, an arrangement that has itself attracted public debate. See our page on the Duchy of Cornwall and HMP Dartmoor.
Is radon dangerous to people living in Princetown?
Radon affects many homes on Dartmoor, and the UK Health Security Agency publishes maps and advice. Household testing kits are cheap and widely available.
What happens to staff while the prison is shut?
Staff were redeployed to other prisons in the region. Official updates appear on GOV.UK and in reports from the Independent Monitoring Boards.
For details of every working prison in the country, see our complete UK prison list, or our history of HMP Dartmoor.
