For 50 years it was a place which remained a mystery to the outside world unless you got on the wrong side of the law.
But now, even the most law-abiding citizens have been able to glimpse inside the previously unknown world of a men's jail as the gates to a former prison were opened to raise money for charity.
For those who thought prisoners these days get an easy ride, the tours of Blundeston Prison, near Lowestoft, have swiftly showed what life behind bars is really like.
Although the more modern J Wing has good – if very cramped – facilities, visitors have been shocked to see tiny, dilapidated cells shared by four prisoners in two bunk beds.
'They all think it's a cell per prisoner,' said tour guide Dennis Williams, a prison officer at Blundeston for 23 years. 'The multi-cells really surprise them.'
He described what he called the 'cat and mouse' game the guards had with misbehaving prisoners, which include one man clinging to a vehicle leaving the site in a bid to escape. He was spotted down the road and subsequently returned to prison.
Mr Williams also revealed how deliveries of clothes from friends and relatives were banned because officers would find drugs in the hems of trousers. Prisoners had to save up and buy trousers direct from shops. And meal serving areas had to be split into smaller halls in a bid to prevent trouble brewing.
The Official Secrets Act prevents Mr Williams from revealing details about the jail's most famous inmates, Reggie Kray and the so-called Lotto lout Michael Carroll.
But amid all the physical quirks of the prison – which included its own mosque and led to a huge increase in prisoners taking up Islam – one of the things that comes over most strongly is the community in the jail.
Jason Oliver, from Stradbroke Masonic Lodge, which has organised the tours, said: 'It was an ideal prison in many ways. Prisoners would come in with little or no hope of doing anything but this prison officially had some of the best statistics for re-educating people.'
The tour shows the education and training blocks set aside for prisoners, with cellmates able to take qualifications and courses in a huge variety of subjects – from basics such as English and maths, to new trades such as plumbing and engineering.
Rachel Cossey, who taught maths at Blundeston for eight months before it closed, said: 'You could actually get a job at the end of it. They actually cared about people.
'In a prison without rehab, you don't get a person at the end of it. You get someone in the system who's going to be a prisoner again.'
There will be one final chance to look around the prison at an open weekend on October 15 and 16 before demolition work starts on the site, which is due to be turned into homes.
Have you been on the tours of Blundeston Prison? Email andrew.papworth@archant.co.uk
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