By Jemima Laing
Dartmoor Prison has a colourful history but its days may be numbered
Many of the 26,000 people who visit Dartmoor Prison's museum each year think the granite building is already closed.
They often express surprise that they cannot have a tour of the interior - that is because it is a working prison housing some 600 men.
But in future those visitors may get their wish if the predictions in a leaked Ministry of Justice document come to pass and the prison is closed.
It would mean the end of 200 years of incarceration in the prison built in 1809 by Napoleonic prisoners of war.
During the war with Napoleonic France thousands of prisoners were taken and confined in prison ships so a prisoner of war depot was planned at Princetown.
It took three years to build and construction was completed in 1809, three years later the French prisoners were joined by American prisoners of war taken in the war of 1812.
At one time the prison population rose to almost 6,000 - many of them died and were buried on the moor.
It was not until the French and American wars were concluded in 1815 that repatriations began.
The prison sits in an isolated spot at Princetown on Dartmoor
French prisoners also started work on Princetown's St Michael & All Angels Parish Church, digging the foundations and erecting its stone walls.
The building was completed by American prisoners.
The prison was reckoned in Victorian times to be the hardest and most severe in England and has been in constant use since 1850.
In 1917 all convicts were withdrawn from Dartmoor, and it was used instead to confine 1,100 conscientious objectors who had refused military service.
There have been a number of mutinies over the decades but the most serious was in 1932 when foul food led to an uprising.
There were no deaths but much of the prison was seriously damaged and many records destroyed.
There are also a number of literary references to the prison, most notably in works by Arthur Conan Doyle and Agatha Christie.
But now it seems the major attraction of the location when it was built - its isolation - is in the 21st century becoming one of its major drawbacks.
Juliet Lyons from the Prison Reform Trust said in July 2010 the "old and isolated" facility should eventually be closed or turned into a heritage museum.
And the leaked Vision for Estate report obtained by the BBC says a new jail will be built in east Cornwall to provide places for inmates.
The MoJ said in a statement it did not comment on documents which had allegedly been leaked.