Jonathan Aitken's time in prison comes under the spotlight in his new autobiography, Porridge And Passion. The disgraced former Tory minister tells Hannah Stephenson about how, despite his loss of wealth, he has been spiritually enriched.

He was once the golden boy of the Tory Cabinet with a circle of powerful friends. Some of those pals remain, but now Jonathan Aitken also invites ex-bank robbers and other jailbirds to his social gatherings.

Indeed, at his wedding reception two years ago, the disgraced former Tory minister's guests included six ex-Cabinet ministers and the same number of ex-cons.

The 62-year-old, who in 1999 served seven months of an 18-month sentence for perjury and perverting the course of justice, says his time in prison changed him and gave him spiritual enlightenment.

He went on to study theology at Wycliffe Hall, Oxford, and now devotes much of his time to supporting prisoners and their families as well as being an outreach speaker and author.

Jonathan knows that sceptics will sneer in disbelief at his sincerity, but he's undeterred. He has just written Porridge And Passion, the sequel to his bestseller Pride And Perjury, which takes his story from when he was sentenced at the Old Bailey, to his incarceration at Belmarsh, Standford Hill and Elmley prisons.

What did he learn from prison?

''Leaving aside a few practical things like how to start a car without an ignition key and how to enjoy rap and reggae music, I learned that none of us are whole unless we've got in touch with our spiritual dimension. To me, it's meant a lot of work on applying the Christian faith and teachings to my own life.''

Life has changed a lot for Jonathan in the six years since he went to jail after he lied to the High Court during a libel action against The Guardian newspaper and Granada television.

He tried to cover up the fact that he allowed aides of the Saudi royal family to pay his £1,000 hotel bill during a stay at the Paris Ritz, claiming his former wife Lolicia had paid the bill. But it emerged that the then Mrs Aitken had been in Geneva when the bill was settled by an Arab business associate of her husband, who was then defence procurement minister.

Jonathan had also drafted a witness statement for his 16-year-old daughter Victoria to sign which backed up his lies.

He was left with £2.4m legal bills which drove him to bankruptcy, forcing him to sell the grand family home in Westminster. He now lives in more modest accommodation at his second wife Elizabeth's home in Earl's Court.

''It was a catastrophic fall and a very painful one,'' he says. ''In prison the name of the game is survival. But there is a lot of human kindness, warmth and humour in a prison, even though it comes your way from people who have done bad things. We'd get by on large doses of gallows humour.

''I managed to get along with colourful characters like Razor Smith, one of the biggest gangsters, and I also got into the flow of the community by having a skill, which was reading and writing.''

Jonathan took to writing letters for fellow prisoners, which made him more easily accepted.

He says his fall from grace has in many ways enhanced his life and that he has a tighter bond with his four children, Victoria, Alexandra, Petrina and William.

''We are a close and loving family. There's one rather poignant story about my daughter Alexandra, who was then 18, coming down on the bus. My daughter and I had two-and-a-half hours of one-on-one conversation, which was lovely.

''I thanked her for giving up her whole day to come and see me and she said, 'Daddy, don't thank me, I've loved it. Do you realise that we've never had two-and-a-half hours of one-on-one conversation? All those red boxes, ministerial phone calls and everyone else got in the way, until now'. That really stabbed at my heart. I'd always been too busy.''

However, in 1998, a year after his libel action collapsed, Lolicia divorced him.

''I understood why she wanted out and we are on good terms now. The whole drama was just too big and too much for her. She saw the big flaws in my character even more clearly.''

Among those were his infidelities. In his old life, Jonathan was a ladies' man, gaining the nickname the Commons Casanova among inner circles. He dated Margaret Thatcher's daughter, Carol and had an affair with Soraya Khashoggi.

Weeks before he was due to marry Lolicia he slept with Soraya again and from this fleeting liaison came their daughter Petrina, whom he didn't find out about for 18 years.

It was only when his other daughters, Alexandra and Victoria, met her at a party and spotted the resemblance that the secret was out and, after DNA tests were conducted, she was warmly welcomed into the family.

''I do regret being unfaithful,'' he says now. ''But I wasn't the kind of Casanova I've been described as. There were no big affairs, it was much more occasional encounters which very often happened in foreign cities.''

Being in prison allowed him time to reflect on his mistakes.

''The kind of person I was then (before his downfall) was outwardly powerful, rich and rather insensitive to other people's feelings. Inwardly, I was full of pride and arrogance. It's not as though overnight I've become a saint. I still wrestle with a lot of my little demons like pride but at least I try and wrestle them, which some people see as improvement.

''Defeat, disgrace, divorce, bankruptcy and jail are a pretty good royal flush of crises by anyone's standards,'' he reflects.

''I found being banged up in a cell for long periods quite a cleansing and chastening experience. I had a long time to think about where I went wrong in life.''

He is now married to Elizabeth Harris, ex-wife of the late actors Rex Harrison and Richard Harris and his own cousin Peter. She's an old flame he met again at a film screening in 2001.

''We had a very chaste, Victorian courtship,'' he recalls. ''It must have been a surprise to her for our evenings to end with polite kisses on the doorstep when both of us may have been inclined to take it much further. But we were going through a period of caution and restraint.

''One of the things that binds us is the fact that we've both been through turbulent passages in life. Mine have been very public dramas but she's had her own very private dramas of being married and divorced to two famous film stars and having all kinds of private sadnesses in her life.''

He has welcomed Elizabeth's three grown-up sons with open arms and the talk of the household at the moment is weddings as her second son, actor Jared Harris, is marrying the actress Emilia Fox, daughter of Edward Fox, later this year.

He did have a chance to re-enter politics when 200 signatories in the local Tory party presented their petition to have him reinstated as candidate for Thanet South, but Michael Howard said there was no place for him in the parliamentary party.

He is philosophical about Howard's decision now.

''I walk past the Palace of Westminster very often but I don't have great pangs of regret. Life has been richer and more colourful and varied since then. I feel more fulfilled now.''

* Porridge And Passion, by Jonathan Aitken (Continuum, £18.99).