STEPHEN Carlin took a major gamble in life when he moved from civil engineering into stand-up comedy and writing.

However, the Airdrie-born performer reveals his life was once a series of gambles. Stephen was, in fact, a professional gambler, a betting man so hooked he was on the verge of becoming homeless.

"I guess I've gambled away tens of thousands of pounds," says the comedian who appears on the likes of Comedy Central's The Alternative Comedy Experience.

"I don't really want to count up the amount I've blown. I think I'd find it too scary."

He added: "I've got a friend who had a cocaine addiction, who worked out that what he'd spent on drugs would pay for two Aston Martins. I'm scared to think what sort of incredible cars I could have had."

Now one of the country's best stand-up comedians – and rated by cult comic Stewart Lee in his all-time Top Ten – next month, Stephen will be appearing with a new stand-up up show at the Edinburgh Festival. And the theme? His life as a gambler.

The 37-year-old admits as a youngster he found betting shops tempting.

He said: "Betting shops also had this enticing allure, the frosted glass windows, and it was a rites of passage thing, like going to the pub.

"On top of this, my parents would only ever gamble on the Grand National. But I was always good at maths at school, good with numbers and stats. And being cleverer than everybody else I really believed I could beat the system."

Stephen began making small bets, building up along the way. Meanwhile, he had always had a hankering to be a performer of some sort, but pressure to get a 'real job' saw him study Civil Engineering.

"I didn't know many degenerate, waster artists," he said. "I didn't know that I could become one."

He couldn't. His epiphany came during a job interview.

Stephen added: "I felt the job was there for the taking, and the interviewer then began to talk about working 12 hour days and a half day on a Saturday, and you had to get to whichever site in the west of Scotland.

"And I remember thinking; 'Not only do I not want this job, I don't want any job in engineering'."

Stephen took off to London, applied (unsuccessfully) to drama colleges and paid the rent with temping jobs. But while he waited for a performance career to kick off (in whichever form) he believed he could make his fortune as a part-time professional gambler.

"I remember betting on the World Cup in 2002 and walking into the office in London where I was working and showing my colleagues the £1000 I had just won.

"There were times I won a lot, then lost a lot. But I was in denial. When I'd go 10 grand in debt I saw it as a temporary situation. It's amazing the lies you can tell yourself. And it was hard to stop because until that time you think you can win it all back. When you stop you know it's gone for ever."

Stephen's betting became worse. He won't work out how bad it got, but he lost 'many tens of thousands'.

He also admits it was difficult for his then-partner.

"It got the point I'd ban her from the room if I were going on-line to bet," Stephen said.

"I didn't want her to see what was going on. Then I blamed her for not stopping me."

Stephen managed to quit. The reality dawned when he couldn't pay the rent, the arrears were frightening, and he faced life on the street.

Meantime, he'd watched a lot of stand-up and one night dared himself to have a go.

"I fluked it," he says. "I remember doing an obscure impression of Alec Guinness, and the audience not getting it, and me berating them for that. But it worked. And it was like a first hit of drugs. You want that high again. Then you appreciate you need to get good at your craft."

The big shift from relative obscurity to success came about when Stewart Lee asked Stephen to support him on tour. His career was off and running. And now he has a new show about gambling, laden with themes such as responsibility and self-deception.

Stephen admits any adrenaline rush he once enjoyed from gambling now comes about from stand-up.

"It's great to be able to get up there on stage and speak to complete strangers about anything that takes your mind.

"Yet, at times I think this is complete madness and wonder what the hell I'm doing."

He's never tempted to gamble? "I buy a Lottery ticket occasionally, but I don't expect to win. And I did play a scratch card on an EasyJet. But I know gambling can't make you rich."

He adds, grinning: "I still think about the Mark Twain line: 'There are only two times in life when a man shouldn't gamble; when he has money and when he hasn't."

l Stephen Carlin, The Pleasance Courtyard, Edinburgh, July 31- August 26.