Gary Mulgrew, one of the 'Natwest Three' extradited to the US to face fraud charges after the collapse of Enron, reveals how he has picked up his life after serving time in a notorious Texas prison.

By Hannah Stephenson.

He's a big guy, Gary Mulgrew. The tall Scotsman looks like he can take care of himself and so he can, as he demonstrated to his fellow prisoners in a tough US jail where he served part of a 37-month sentence for fraud.

The former banker didn't get involved in fights. He tried to remain anonymous, just going by the name of 'Scotland'.

His new autobiography, Gang Of One, charts this time, revealing just how astounding it was he managed to avoid being beaten up in the notorious Big Spring, a Texas prison run by vicious gangs whose violent acts were routinely ignored by the wardens.

He didn't kowtow to any of the racist thugs who approached him to join their gangs, and turned a blind eye to the appalling beatings he witnessed, generally keeping himself to himself, hiding his overwhelming fear behind a bold front.

Not so long ago, Mulgrew was a high-rolling investment banker with NatWest, one of those who earns six-figure salaries, eye-popping bonuses and enjoys all the trappings of success. The type the British public has come to hate.

Then he became known as one of the 'NatWest Three', after ending up in prison for a corrupt deal that played a part in the downfall of Enron - the giant US energy company whose corrupt accounting polices resulted in the loss of 5,600 jobs and 2.1 billion dollars in workers' pension assets in 2001.

Today, he says it's worse being a banker than a convicted criminal.

"Nobody seems to get hung up about the fact that I was a convicted criminal. They get hung up about the fact that I worked in a bank.

"I was a banker and then I was a convicted criminal. That was my first step on the road to rehabilitation."

After a high-profile battle in the British courts (he was never charged or found guilty of fraud that helped destroy Enron by any UK authority) he and two others, David Bermingham and Giles Darby, were extradited to the US in 2006, where they each pleaded guilty only to defrauding their employer NatWest, in exchange for other charges being dropped and to ensure an early return home.

He says he never realised he'd committed a criminal offence and was incredibly naive.

"I made an investment without informing NatWest. I had no idea the investment was crooked, but I didn't tell them because I didn't think they needed to know. I wasn't aware I was committing a crime."

The extradition led to protest marches through Westminster and a special debate in the House of Commons. Would that happen today?

"I'd like to think that in Britain, if Gary McKinnon (wanted by the US authorities on charges of hacking into Nasa and Pentagon computers from his home in north London) was going to be extradited, people would march. I certainly would.

"Would they do it for bankers now? People hate bankers," says the Glasgow-born author, who spent years of his childhood in a care home.

In Big Spring he had meltdown moments when panic attacks took hold, and he had nightmares about the beatings, being chased and the sense that he wasn't going to get out.

But his desperate need to return to the UK prompted him to go for plea bargaining and kept him focused while in prison, he says. Just days after he was extradited, his ex-wife Laura took Mulgrew's five-year-old daughter Cara Katrina to Tunisia. He was, and still is, desperate to find her.

"If you have an overriding need to go home, as I did, you'll find strength. I don't think I'd have coped as well in prison had I been a childless father."

His ex-partner Julie looked after his teenage son Calum, now 16, when Mulgrew was in prison: "I hadn't heard from my daughter for a number of years, my son Calum was getting older, life was moving on."

Mulgrew served his time in seven prisons, including Big Spring, before being sent back to finish his sentence in the UK, and was finally released in 2010.

When his daughter recently turned 10, he sought counselling.

"I had survived so much and when I got out of prison I ran around building everything up again, but inside I was dying. Her turning 10 was a watershed moment for me."

Hiring a private investigator, Mulgrew discovered that his ex-wife had married a Tunisian and that his daughter was at a Tunisian school.

Even if he were to find her, it would be difficult to get Katrina back, he agrees.

"I have no legal right to remove her from Tunisia, but more important than the law is the reality of where we are. It's five years ago, she's turned 10. Maybe it's too long, maybe I'm too late."

Laura has written occasionally to Calum's school, and the letters always have a Tunisian stamp.

"The book is for the belief that I will find her and I haven't managed that yet. Parental abductions are different because at the end of the day, she's with her mother, and Laura is a loving mother and good person. You imagine Katrina will have a good life.

"The reality is that even if I were to find her, it might not be a good thing. I have to do the best for Katrina, so even if that means I get contact but she stays in Tunisia, that's what I'll do."

Mulgrew insists he was never motivated by money.

"I had a 17-year career with NatWest and the last two or three years I'd made a lot of money. I earned more than £1 million at that point, but I was never motivated by money. I was from a children's home in Glasgow and wanted the acceptance.

"I didn't have a Rolex, I'd had the same car for 14 years. I did have a big house but I didn't flash money around. I was amazed people paid me that well."

Today he has lost all of his fortune and has little in his NatWest bank account. Divorce, legal costs and paying back NatWest have wiped him out. The big house was sold, legal fees ran into millions of dollars and even if he'd won the case in the US, he wouldn't have been able to claim the fees back, he says.

Today he lives in Brighton and has a couple of business interests, running a building company in Lewes with his best friend, and has made investments in pubs.

The experience of prison has left scars, but they're not as lasting as those he bears through the separation from his daughter, he reflects.

"I felt when I came back I was hardened. I lost faith in institutions and the law. Now, the thing that's hard for me is that my daughter's missing. It's like a hole in my heart."

:: Gang Of One by Gary Mulgrew is published by Hodder & Stoughton, priced £16.99. Available now