Labour's toughest Home Secretary seems to have gone tender. The man who once wanted to ban hoodies now wants to hug them.

David Blunkett spent ten days behind bars with young offenders for a reality TV show and emerged believing that society needs to be tough with them, but also understanding.

He said: “I talked to them a lot, I learnt about grime - a form of music culture - we had art therapy and woodwork. Their problems were all about peer pressure and breakdown of the family. Often people just got into the wrong set.”

The show was set in a specially refurbished prison in Scarborough. The 17-year-olds had all been in trouble, for drugs, assault or theft, but had never been in jail. In with them were prison warders, former convicts and criminologists.

“They were shocked by the sheer deprivation - no girls, no cigarettes or football matches. We had to make sure they didn't self-harm in the first 24 hours. Two couldn't stand it and had to leave,” he said.

Mr Blunkett insists he was not playing the role of Davina McCall. “This was no Big Brother. It wasn't even The Apprentice. We didn't seek to humiliate anyone,” he says. According to Mr Blunkett, all problem teenagers should spend some time behind bars. “Schools should take children to prisons and, with the help of inmates, they can discover how ghastly it is.”

It was a learning experience for Mr Blunkett, too. “The programme made me realise we need a two-handed approach - we must be tough, with a clear framework for living, but we must also be more understanding and take action that redeems people's behaviour. We mustn't simply believe that by locking people up we have solved the problem.” The man who presided over a large increase in the prison population now says that there are far too many people in jail.

“In an ideal world, prison would not be the place for young people. If you take the mental health side, rather a lot of people shouldn't be in prison.”

He also feels uneasy about locking up women. “I don't think they should be in these jails. I think they should be in other forms of semi-secure units with tagging. A lot of people in Holloway self-harmed, which showed their lack of self-worth, but it was also a real cry for help.”

Mr Blunkett seems to have had a conversion. “When you are Home Secretary, you have to sound hard, you have to deal with people who don't get the message that crime is wrong and reassure the public that you are on his side.” However, he adds: “I do wish I could have done things differently as Home Secretary. I want tough sentences for heinous crimes, but also really intensive community restorative justice. We did do the first and we didn't do enough of the second.”

Mr Blunkett has been blamed for the rise in the prison population, because he introduced indeterminate sentences. He says, however, that judges misinterpreted the law. “These sentences were meant to be for rapists, not for people who should be sent down for a year or 18 months. There has been so much misinterpretation and perversity by those delivering the criminal justice system.”

He adds that it is insufficient to simply wield a stick: “It is partly parenting and partly the harshness of the world we now live in. Poverty is not the cause, but insecurity and instability. I hope this programme makes people feel you can be tough, but you need to help people as well.”

Banged Up with Blunkett will be shown tonight on Five.

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