Expo 93 is the title given to this fiesta of openness at Britain's most notorious and forbidding jail. The mist-covered, granite monstrosity is offering a two-week display of the best of prison life.
'We want to make the public aware that we are on the cutting edge of therapeutic aid and training,' said Peter Lake, Dartmoor's assistant governor. 'We can't throw open the doors to everyone, but we have invited the Women's Institute and other basic, honest citizens to see the results of our work. We are doing our best to address the opinion that Dartmoor is a Victorian and punitive prison.'
Mr Lake was referring to a damning report by Judge Stephen Tumim, Her Majesty's Inspector of Prisons, who called Dartmoor a 'penal dustbin' and urged the Home Secretary to close it if it could not be transformed.
The prison governor, John Powls, arrived at Dartmoor in the wake of the report. 'I saw it as my job to put right what Judge Tumim recommended,' he said yesterday.
A five-year refurbishment programme began: all prisoners will have their own sink and toilet within the year. More training and therapy will be available; less time will be spent in the cells.
'Expo 93 is a celebration of all we have achieved,' said Mr Powls.
Three rows behind him the mood was grumbling, dour. A group of inmates bemoaned the 'censored' version of prison life as presented by Jimmy Young. The prisoners he was interviewing had been especially selected to give the prison a smooth gloss, they said.
'This prison is the last stop,' said one prisoner. 'That's the real truth of the matter. If you do something wrong at another prison, Dartmoor is used as a threat to keep you in line.'
On stage, Jimmy Young's show rolled on. He asked the questions his radio listeners wanted to hear. To a prisoner: 'Didn't you think about your victims?' To a female prison officer: 'Don't you get offended seeing saucy pictures on cell walls?'
To the governor: 'Is it right that these criminals should be here enjoying themselves?'
No, was the reply, but there should be a balance: just being in jail is punishment enough. Extra effort should be channelled into rehabilitation.
After the show Jimmy Young said his conversations with inmates and staff had been moving. 'My eyes have been opened,' he said. 'Here we have 500 human beings who have got flaws. We all have flaws. These men are not saints but they deserve to be treated like human beings.'
The few prisoners who stood around nodded in agreement. They needed reminding.