Reformed killer reveals how wife's death made him realise the horror he had visited on others

The love of Caroline McNairn, who became his wife in 1993 not long after his release, helped him survive the transition. She was everything he was not: respectable, middle-class and one of the finest Scottish artists of her generation.

But Collins, a few months short of his 60th birthday, is now back in something approaching the hell of his past. McNairn died suddenly aged 55 at the end of September, just a short time after they learnt she had cervical cancer, and Collins is struggling to cope with his grief.

His loss has also provoked a profound realisation of the impact of his past, both on others and on his own life.

In a moving interview with Scotland on Sunday in which he paid tribute to "the love of my life", Collins revealed how the death of his wife immediately evoked painful memories of his brutal past.

He said: "It happened unbelievably quickly. It seemed that one minute Caroline was there, the next she was gone. I'd left the room at the Borders General Hospital and when I went back, our friend was crying and telling me to talk to her.

"She said: 'Hugh, she's gone, but the last thing that goes is the hearing. Talk to her'. I couldn't believe it. Only a few hours earlier, she'd been laughing and joking with me and her best friend, Andrew Brown. But it was for real. I took her in my arms and the tears were streaming down my face and I told her she was the love of my life, that I'd always loved her and always would.

"I held her in my arms, knowing she was dead and wondering if any of my words had reached her in time, and those minutes brought home some hard truths.

"I knew how utterly devastated I felt, and I remembered that I had done that to a family many years ago.

"I'd taken the life of a young man and destroyed his family, and now, more than 30 years later, I finally knew what that sort of pain felt like."

Until his wife's illness and diagnosis, Collins had been in the process of making peace with himself. The couple moved from the bustle of Edinburgh's High Street to a cottage on a Borders farm near Walkerburn five years ago. Collins' garden became a workshop dotted with stone sculptures, from the first piece he ever completed in the Special Unit at Barlinnie, a pair of crossed feet in red sandstone, to more recent and more accomplished works.

McNairn had little time to paint during these last few years as she travelled back and forth daily, helping care for her elderly father, the amateur artist and art collector, John McNairn, until his death at 98 last year.

But the couple were planning a joint exhibition of their art, and McNairn had just completed organising a joint exhibition of her own paintings together with those of her father and grandfather at Hawick Museum before she fell ill.

Collins is a striking figure, not least because of the scar left by a meat cleaver that opened him up from ear to throat in his youth, but the mental scars of his past are deeper.

It would be impossible to overstate how heavily the ghost of his victim, Willie Mooney still burdens him more than three decades on, or how deeply he regrets spending his best years in some of Scotland's grimmest jail cells.

He said: "As a young man, you think a life of crime and violence earns you respect. People fear you, and you like it. You get to like the buzz from the adrenaline when you fight, and if you're winning the fight it gives you an incredible high.

"But you can be the hardest guy in your area, your town, or the whole of Scotland and there will always be someone harder, or more vicious, or someone who just gets lucky. It's a mug's game."

He and Mooney had a history Collins explained in his first book, Autobiography of a Murderer. Mooney had beaten him up badly on a previous occasion. They knew they were going to fight, that they would both have knives and that one or both would be badly hurt.

He said: "This is the side of it that most young lads who carry knives won't know until it happens to them. It's a sickening feeling to strike a blow with a knife and look into that person's eyes and see the fear and horror there, especially if they know they're dying.

"I stabbed other people in fights, I stabbed prison officers inside. I was supposed to be this raging animal in jail, but I was just a scared laddie. When I struck with a blade, I always felt sick. I felt like a monster.

"When I got out of jail after the lifer, people wanted me to apologise for what I'd done and I didn't want to seem weak. I didn't want to be bullied and I maybe came across as arrogant or unfeeling.

"But the truth is I was overwhelmed.

"What words can you find that are adequate when you've ended someone's life?

"Of course I'm sorry I killed Willie Mooney. I'm sorry for it every day, and have been every day since it happened.

"What's happened to me since Caroline's death is that I really understand that sorrow. Knowing I'll never see Caroline again in this world, I truly understand the depth of his family's loss. If I could change the past I would, but none of us has that power."

Collins met his wife-to-be in 1990 when he was allowed out of prison once a week to work in the now defunct 369 Gallery, run by Andrew Brown. Collins gives McNairn all of the credit for his sanity and for keeping him out of trouble.

From the moment of his release in 1992 was assured, the offers to go back to a life of crime started to roll in, but Collins is grateful he wasn't even tempted to sink back into the world he knew.

He said: "An awful lot of people put themselves out for me, welcoming me into their lives, especially Caroline and her family. What a betrayal of their trust it would have been if I'd gone back to a life of violence, and what a gift to the know-it-alls who said people like me could never change."

The most important thing in his life has been his marriage. "Caroline was my saviour, my love, my best pal, she was everything to me."

"We could argue at times like the best of them, but we worked at it. Marriage is hard. Fidelity can be hard until you realise the people throwing themselves at you are doing it for dubious reasons.

"Too many people walk away because they say the passion's gone. They grab what's on offer and don't care about the destruction they leave behind."

Collins might well be one of the best examples of rehabilitation Scotland has seen. By his own admission, he was once out of control. His notoriety developed in jail for his persistent attacks on warders.

Provoked by a hatred of authority first forged in borstal, and hardened by what was then a brutal and violent regime, he tried to kill three prison officers within months of his conviction and became known as Scotland's most dangerous prisoner.

Unrepentant and untamed by months in solitary and an ever-harsher regime, he became a natural for Barlinnie's Special Unit, the last-chance saloon of its time but long since defunct.

Introducing Collins to art and placing trust in him worked like a charm. McNairn was the final piece that secured his redemption.

Collins plans a lasting tribute to his wife and will travel to Italy in the new year to collect a piece of marble, from which he will create McNairn's image.

Over four months, Collins and McNairn learned that she was ill, received a diagnosis of cervical cancer which had spread to the lungs, endured radiotherapy treatment, only for her to die at the end of that short spell.

With tears running into his newly-grown beard, Collins added: "Caroline told me towards the end that she was scared of what was coming. I told her I'd be right behind her, and since she died there have been times I've just wanted to lie down, not drink or eat and wait to join her.

"But she told me I had to get on with my life and I know that's what she wanted so it's what I'm trying to do. But it's hard. I fell in love with Caroline the first time I saw her, and the feeling never dimmed. I miss her so much."