So, are drug users sick or simply criminals?

The question prompted a furious row between Russell Brand and Peter Hitchens. But who's right? Paul Peachey was granted rare access to a prison rehab scheme to find out the truth

When Simon Pearce was jailed for the 13th time, he finally recognised that the game was up. Heroin and cocaine had cost him his liberty, his family and almost his life. "I've done jail and I've swerved nuthouses by the skin of my teeth," he says. "The only thing that was left for me was death."

He is currently serving six years for robbery. He kicked down someone's door, beat him up and robbed him. "I have done some despicable things," he says. "That's where addiction took me. I would sell my grandmother for a bit of gear."

Mr Pearce says he is now a man transformed. He is thin and looks a lot older than his 33 years, but for the last 17 months has been clean and sober. "I really feel this prison sentence saved my life," he says.

He is with a group of recovering addicts at The Mount Prison in Hertfordshire, a category-C prison of nearly 800 inmates. The fact that he is off drugs is a success for abstinence-based recovery, a form of treatment championed by former drug addict and comedian Russell Brand in a BBC documentary to be shown tonight.

At its heart is a 12-step programme of therapy, forcing the user to confront addiction, behaviour and the damage it causes. The course treats dependence class-A drugs as an illness, not as a crime. Such an approach has attracted the ire of right-wingers, like commentator Peter Hitchens, who in a bad-tempered Newsnight debate last week with Mr Brand, claimed that the government had given up on promoting stiff jail terms to deter drug-related crime.

On Dixon Wing, home to some 60 drug addicts who, like Mr Pearce, have willingly agreed to take part in an abstinence-based programme, the idea that longer sentences would deter is treated with scepticism. The programme, which lasts a minimum of five months, is coupled with a rigorous drug-testing regime. One breach of the rule may be enough to see an inmate kicked off the programme.

Inmates can be given methadone – a heroin substitute – but only before they start the programme and the men are segregated from other wings to avoid temptations of drug taking. Nets strung across the gardens inside the prison walls are testament to the prison authorities' difficulties in preventing drugs from being tossed over the walls. Noticeboards near warders' rooms display photos demonstrating how contraband is smuggled into the prison in other ways: inside biscuit boxes, radios and furniture.

"If I wanted drugs, I would walk down there and get drugs," said Mr Pearce. "It's as simple as that. But this has changed the way I think about drugs."

The inmates say it is the most difficult thing they have done. Of 100 who started the course last year, two-thirds completed it. "If it's only six weeks, they can keep the mask on, they can play the game," says Nick Messikh, the treatment manager at The Mount, himself a former inmate who recalls leaving Wandsworth Prison with nothing but a plastic bag and a drug habit. "When you get them for four or five months, the real people come to the fore. You get a lot of anger, a lot of remorse."

Inmates reject the idea that it is an easy option. It opens with them drawing up a list of more than 100 ways in which drugs have damaged their lives. They have to read it in front of others in the group. "I've known big strong blokes who would be intimidating on the wing," says one inmate, serving time for arson. "They'd break down and find it hard to stop crying."

The programme, developed for alcoholics in the US and later modified by a Minnesota hospital, is spiritual in tone. Step five is: "We admitted to God, to ourselves and to another human being the exact nature or our wrongs."

"It's like putting up a mirror and seeing what I have done to myself. It's quite emotional," says Jamie Harris, 36, serving seven years for drug smuggling. "I wanted to blame everyone else. It was a big decision to make to go on this programme. It's been a life changer."

RAPt, the Rehabilitation for Addicted Prisoners Trust which runs programmes in 26 jails, says that the schemes make economic sense. It costs about £2,000 for each prisoner. Keeping one inmate in jail for a year costs £41,000.

Nearly half of all adults are reconvicted within a year of leaving prison, according to the Prison Reform Trust, rising to 67 per cent for those who have served more than 11 sentences. For those that have been on the RAPt programme, it falls to 38 per cent.

Such abstinence programmes remain a small part of overall prison drug treatments. For the last year however, the Ministry of Justice has begun piloting drug recovery wings at five jails across Britain.

The programme at The Mount deals with the first five steps of the programme. The inmates are then returned to the community for secondary treatment and to try to resume their lives. Staying off drugs is the difficult part after moving from the supportive environment of the prisoners' group. Those that return generally have struggled with a return to normal life.

"They normally say they've not been able to hold down a job, moved back to an old circle of friends and not been able to resist the pressure," says the prison's governor, Steve Bradford. "If we can give them somewhere to live and find paid employment we know that their chances greatly increase."