Boyle has already told his own story in detail in two autobiographies, A Sense of Freedom and Pain of Confinement.

They describe his upbringing in Glasgow's Gorbals, his early entry into the world of violent crime and his incarceration in Barlinnie's special unit, where he turned his life around, met his wife and discovered art.

Now, Boyle lives in a 12-room house in Edinburgh's new town with psychotherapist Sarah Trevelyan and their two children who both attend private schools.

His sculpture has made him rich and he has integrated himself into polite society. A recent newspaper story put him sixth on a list of desirable people to meet at an Edinburgh dinner party.

But when Boyle reads from Hero of the Underworld at the Edinburgh International Book Festival on Friday night, he is not planning to mind his manners too much.

The book is based on the teenagers he met at a centre he ran in the city after being released from prison and paints a dark and uncompromising portrait.

"It is certainly not bedtime reading," he says. "It's pretty strong stuff and it's certainly nice to challenge the audience."

Book festival caused controversy by stating Boyle did not commit murder of which he was convicted

After his reading, Boyle will take questions from the audience and knows the subject will quickly return to his own past. He remains happy to talk about it, but stresses how much his life has moved on from his early years.

The book festival caused a small row of its own when it printed its 1999 programme, in which it states Boyle was "imprisoned for something he did not do".

A Conservative member of the Scottish Parliament demanded the brochure be withdrawn, pointing out Boyle was convicted of the murder of gangland boss William 'Babs' Rooney and has never successfully appealed.

Boyle himself refuses to get embroiled in the argument: "I can only say what I've consistently said that I did not do that murder that I was convicted of," he says.

He knows, though, that he will never fully escape his time in prison and his hardman reputation. Yet when his next novel is published he is hoping to take his readers by surprise and confound those who insist on drawing parallels between his life and work - the story is an erotic comedy about the Mona Lisa.

Boyle's next novel is an erotic comedy about the Mona Lisa

"It's about a guy who comes from an Edinburgh housing estate and he's a telephone kiosk cleaner at a firm that is taken over by a European company.

"He's transferred to Paris office and is cleaning in the Louvre and becomes obsessed with Mona Lisa. He finds way to steal the Mona Lisa and take it back to its rightful place which is in Pilton."

Pilton is a housing estate in Edinburgh. Why Pilton? "Because art's for the people not the elite," Boyle says.

Valued at more than £10,000 a piece, his own sculpture is certainly out of the price range of most people. As well as his new writing, Boyle is working on a major exhibition of 45 works to go on display in Barcelona in 2004.

He says he is the sort of person who only needs four hours sleep a night, so he gets up at 4am and writes for four hours before he takes his children to school. He also spends about half the year in his second home in the south of France, where he has more time to work undisturbed.

Boyle met his wife during his time in Barlinnie's special unit for violent offenders

He now has two living children, Suzi, 15, who wants to become an actress, and Kydd, 12, who is mad about the Glasgow football team Celtic.

So 17 years after leaving jail, Boyle's life appears to have brought him everything he could want. But he has admitted since he turned 50 more than five years ago that his thoughts have increasingly started to dwell on death.

"I don't fear death, because I have been so close to it. My mother died while I was in prison and, four years ago, my eldest son, James, was stabbed to death.

"He was a drug addict and his death was something I had almost been anticipating - I always thought he would overdose. It was terribly painful.