Martin Compston at 20th anniversary screening of first film Sweet Sixteen in Glasgow

Line Of Duty star Martin Compston said he owed his career to Sweet Sixteen and the teacher who put him up for the audition, as stars from the Scottish film attended a 20th anniversary showing in Glasgow.

The sell-out screening was the first time the actor, originally from Greenock, had seen the Ken Loach drama for more than 15 years.

Compston, who now spends part of the year in Las Vegas with his wife and young son, thanked fans for coming to see the special screening during the Glasgow Film Festival.

“Life is a bit hectic at times now, so, I don’t really think I considered how much this would mean to me today being back here 20 years later,” he said.

“The fact all these people are here to see it again really means a lot.”

“I owe Paul (Laverty, Sweet Sixteen’s writer), Rebecca (O’Brien, producer), and Ken (Loach), I owe them my whole career.

“They took a chance on me 20 years ago and I’m still blagging a living at this now.”

Sweet Sixteen tells the story of Liam who was a teenager from a troubled background who wants to start life afresh once his mother has completed a prison sentence.

But he soon becomes embroiled in gang life in an attempt to raise money for his family, with the film set against the backdrop of Greenock, Port Glasgow and the coast at Gourock.

Now 37 and currently staring in STV’s Our House, Compston has his St Columba’s High School teacher Mr Harkins to thank for encouraging him to audition when he was a 17-year-old.

“I saw (Ken Loach film) My Name Is Joe and it had blown my mind because I never knew people who spoke like me could be on the big screen so it just changed my idea of what cinema could be,” he said.

“Just by chance they were having open auditions at my school the following year and it was my teacher who said: “Look, they’re talking about this kid they’re looking for and I think it’s you.”

“I mean, looking back, it probably meant a wee gobshite who had far too much to say for himself.”

Sweet Sixteen premiered at the Cannes Film Festival in 2002 and went onto win the Best Screenplay Award, but even with the praise of critics Compston said he has not watched it for at least 15 years.

“I don’t like watching myself back, I can watch it once, and also probably my voice of the time is like fingers on a chalk board to me,” he said.

“The reason I think I was so good is because I was so raw, but when I look back I can see how raw I am going ‘why are you doing that?’.

“It was a Catch-22, the fact I didn’t know what I was doing made it so good but now looking back I’d be going ‘I wish I never done that’.”

At the anniversary screening, Compston and co-star Annemarie Fulton were joined by director Laverty and producer O’Brien, with Loach joining on a video-link to speak to the four on the red carpet to make the reunion complete.

Laverty said the film had such a “rich seam of talent” and the 20 years had “all gone in a flash”.

“It’s funny how a film has a life of its own, and I never take it for granted, it’s quite remarkable,” he said, and added people who were born after the film was made were still referring to it and the characters.

“It’s remarkable how it finds its way, and it must tap into something,” he said.