On stage Sean Collins is ice cool. The Canadian comedian thinks nothing of being interrupted by hecklers or allowing an audience member to leave the auditorium to buy him a pint in the middle of a show.

His is so relaxed, it would almost seem an insult, were it not for the fact that he clearly loves his job.

"I've been doing it a long time," he explains. "It doesn't phase me. It's nice going in there having 15 years' experience. I used to vomit before I went on.

"In Canada, they had to delay the first show I did. They turned off the microphone and asked me to get off stage. Soon I realised that getting myself worked up affects my performance in a negative way. I still love it. It's my favourite thing to do in the world."

Some might say that it is not surprising he is so relaxed, considering the amount of drugs he used to take. Now, at 38, he maintains he is free from Class A substances, but he admits that he still smokes cannabis pretty regularly.

"I used to enjoy them, what can I say?" he says of his wilder drug-taking days. "I enjoyed them for a while. I have just calmed down. I just grew up. Those days are from the past.

"Giving it up completely is something I'd never do. I still enjoy a spliff. If you give me a choice between going out and getting hammered on lager or staying in with some really good friends, laughing and having a joint, I would choose the latter."

Despite having worked as a child counsellor on a psychiatric unit in a Vancouver children's hospital, Collins does not analyse the reasons for his Class A usage.

"It was nothing about my upbringing. It was my choice. I don't blame anything like the drugs on anyone but myself."

But he does explain how his former career helped him to get into comedy.

"It was a good outlet," says Collins. "Being funny helped, especially with what they were going through in their life. Kids swearing at me didn't hurt me. That is where I started comedy. It doesn't pay that well before you get yourself established, so I did both jobs at first. After 12 years I got up and went."

Naturally the drug-taking provides a lot of material for his gigs. His latest show he is taking to Edinburgh, Truth, is a story-telling show in which Collins gives us frank and funny anecdotes with an added off-stage voice, his conscience.

The result is pretty hilarious, especially when he and his conscience argue the toss. Like in cases of whether he should have slept with a particular girl or not; or whether he should have taken that acid tab or cocaine.

"It's the easiest thing for people in this day and age to talk about, what you have experienced," says Collins.

"Nobody can steal my material because it happened to me. It's easy to remember as well. I'm terrible with lines. Even in school plays if I had one line I'd say: Happy Easter, everybody!' and it would be Christmas. I have an easier time talking than remembering."

One might think that the cool persona plus the crazy lifestyle would make Collins a rather prickly character, riddled with arrogance and insecurities, but the hidden extra to his personality, and something which he is not shy to talk about on stage and off, is love.

He is engaged to comedian Clare Campbell, whom he met at a gig. They kept in contact for a couple of years as friends before Collins moved to England and they became a couple.

He puts the success of the relationship down to becoming friends first. It is also helpful that, as a fellow comic, she understands his difficult working hours, despite the fact that Collins can be a little more choosy about which gigs he takes nowadays.

"It's the first time that it makes sense to me," he says. "I'm just happy for the first time in my life. It's different this time. She's great."

And with that you realise why he does not take hard drugs anymore, and despite a bleak past and the strange stories he tells on stage, the underlying current in his gig is actually rather uplifting.

u See Sean Collins' Edinburgh preview show, Truth, at Jacksons Lane, Archway Road, Highgate, on July 20, 27 or 28, at 8pm. It is a double bill with Noel Faulkner in Shake, Rattle and Noel. Tickets are £6. Call the box office on 020 8341 4421.