Although he is most well-known for his role as Detective Inspector Steve Arnott on Line of Duty, Martin Compston, a Scottish actor, vividly recalls how he first got into acting as a schoolboy.

A teacher pulled him up in the corridor at St Columba’s Secondary School in Gourock, and informed him that they were looking for children to star in a movie.

“I recall Mr Harkins saying that “what they’re talking about, I think you’re it.” He told BBC Scotland that he believed he should meet them. “That probably refers to a small guy who had too much to share.”

Compston auditioned for and was offered the role of Sweet Sixteen, Ken Loach’s gritty drama. This drama is marking its 20th anniversary.

The story follows Liam, a teenage boy with a troubled past who hopes to start afresh with his mom once she is released from prison.

The backdrop to Liam’s fundraising efforts for the two of they is the Inverclyde town of Greenock, where Compston is from, Port Glasgow, and the coast at Gourock.

It was awarded the Best Screenplay Award at 2002 Cannes Film Festival.

Compston, 37, stated that while it felt like a lifetime ago, it is also a vivid memory. “I recently saw videos of my time at Cannes. That voice, it’s almost like nails on a chalkboard, even going through me. I was like, “What are you talking about kid?” But I’m proud of it.

“It was an amazing time in my life. I’ll always be grateful to Ken Loach (screenplay writer), and Rebecca O’Brien [producer] for taking a chance and setting me up on a path that has led to a very wonderful career.”

Sweet Sixteen will be shown at Glasgow Film Festival on Sunday to celebrate its 20th anniversary. Compston will take part in a Q&A afterward. It is already sold out.

He lives in Las Vegas and Scotland with his wife and their toddler son.

He spoke from his Vegas home and said that he loved it, but Greenock was, and will always be, his home. It’s home to all my family members and friends. It’s a blessing to have two homes.

“I am grateful for the kindness shown to me by people at home, especially Inverclyde. It’s always nice to feel that people care about you in Scotland, but it’s also nice to be alone.

It’s quiet. I don’t have to plan my trips, get dressed up and go to Tesco. I can take the little guy to the park with me and we can have a lot of fun without worrying about the cameras. However, I will be back home next week and home for the remainder of the year. I cannot wait.

“I don’t think we can be more fortunate to have such a dual life. Our Greenock home is in a wonderful spot. My son enjoys it there. He is a very lucky boy.”

Compston stated that he is calmer than most dads because he has to be. Most people would describe me as social, and I loved going out on a night. I am still sociable, but it is important to choose your battles these times. My wife is on the road, so I have to be my own parent. It’s great.

Many people mistakenly believe that Compston speaks English after seeing him with a London accent in Line of Duty. They are shocked when he uses a Scottish accent in his latest drama, Our House.

He said, “I’ve been acting for 20 years so I hope people get the message.”

“People often ask me why I was given an English accent for Line of Duty. But it wasn’t a discussion. I am an actor and it’s my job. The character was originally from London.

It’s difficult, but it’s also another element. It’s hard to go in and do 20 pages of dense dialogue with incredible actors.

“But one of my greatest advantages about being able keep my own accent, is that I feel with the Scots you can turn on some charm.

When asked if Line of Duty would return for a seventh series of Line of Duty, he replied that he was in the same position as ever. Perhaps it’s just because there is more interest in the show and more people want information if we’re coming back.

“But there has always been a huge gap between shows – sometimes up to two years at times – so Jed (Mercurio creator) will take his time. If he feels there is a story to tell, he’ll get in touch. We would all love to collaborate again, but only in the right circumstances.

Compston has cultivated a strong friendship with Jed Mercurio, as well as fellow Line of Duty Actors Adrian Dunbar & Vicky McClure throughout the years.

He said, “We’ve been doing Line of Duty since over 10 years so they’re an important part of my life.” “They are truly some of my closest friends.”

Compston will support Ardgowan Hospice and the group will be going to Greenock Saturday night.

He said, “I called the men and they immediately said, “Let’s do it!” “When it comes down to stuff like this, I love them to pieces – they’re all coming up and will raise a few quids for the hospice.