25/06/2012 18:42 BST | Updated 25/08/2012 06:12 BST

TV Review: Lifers - Chilling And Compelling Insight Into Life Behind Bars

“Unexpected things happen,” is how one inmate rated his chances of a future free from the kind of violence and tragedy that had seen him sentenced to life for the murder of a stranger.

It was a sobering assessment of rehabilitation, but as pragmatic as everything else in this absorbing chronicle of life behind prison bars for those convicted of heinous crimes with minimum tariffs left to the discretion of the judge.

Lifers form an increasingly large proportion of those serving prison sentences in the UK today

It was a diverse bunch of men who were happy to tell the Channel4 team about the goings-on inside the secure walls of HMP Gartree in Leicestershire.

Shaun, a shy outsider had one day “walked out of the club and just knew I wanted to kill someone, it could have been anyone” – in the end it was a woman who had made the mistake of sitting next to him in a restaurant, and he handed himself to police the following day. 12 years later, he had been diagnosed with Asbergers syndrome, had much-higher-than-average IQ and was finishing his pure maths degree. But, despite serving his minimum tariff, he had not been deemed fit for release by a team of charmingly frank forensic psychologists. If they seemed strangely cheerful, I guess that’s how they get through the day.

"Keiron, do you feel bad?"

"In some respects, yes. But I wouldn’t have got any qualifications if I hadn’t gone to prison.”

Meanwhile, Ozzy had killed his friend in 2005 over a meaningless argument over drugs. “If I could go back, that’s what I say all the time… if,” reflected a clearly regretful Ozzy, who spent his time making a mythical shield for his son out of matchsticks.

And there was affable Chris who busied himself taking his pet birds out of their cage - "it doesn't seem right to lock them up," he said.

There was a bit of reality TV jauntiness when Ozzy and co got busted for brewing hooch in the cells - for one man, it was the sixth time, which meant 21 days' segregation. But there was a chilling undertone to this. As Welshman Philip Hegarty pointed out at the beginning of his 30-year mandatory sentence, for a genuine lifer, there really is very little to lose when working out how to conduct himself within the walls, which makes disciplining them a problem.

However many hours they've had time to reflect on their status and what caused it, I can’t believe every prisoner serving a life sentence in this country is as articulate and self-aware as any of this bunch, but their power of expression had a double effect.

It drew us inexorably into their world, thoughts and feelings, but then made it all the more chilling to compare these cheeky chappies against their horrifying charge sheets, particularly the softly-spoken crossword-solver with his contrition for strangling his wife.

All part of the jail's regime are classes, sport, work shifts, hobbies. There, of course, is the central irony - that these men, locked away, gain qualifications, purpose, fitness, routine and purpose - all those things that might have prevented the tragedies they caused, had they had such resources earlier in their lives, either through circumstance or their own limitations.

This plus the video-games on display might make prison life seem all too holiday camp, but the more articulate of the inmates are all too aware of the missing element – freedom, even to make mistakes. As Shaun reflected, “I could have been out there, marrying someone and getting divorced like so many others.”

Arguments about how best to balance the need to protect the public from such undeniably anti-social characters while embracing the potential for individual rehabilitation will wage long after the credits on this programme have rolled, but this was a fascinating, chilling and memorable piece of television.