Having made a big impact appearing in Sam Mendes’ acclaimed war movie 1917, 20-year-old Londoner Anson Boon is now the lead in the excellent new Irish film The Winter Lake. An atmospheric thriller that makes stunning use of the Irish landscape, Boon stars as shy, withdrawn teenager Tom, who relocates to Sligo from Leeds with his mum Elaine (Charlie Murphy).

Though Tom struggles to fit into his new surroundings, he enjoys a burgeoning relationship with neighbour Elaine (Emma Mackey), only to discover she and her dad (Michael McElhatton) share a dark secret. Written by David Turpin and directed by Phil Sheerin, The Winter Lake – which recently premiered at the digital version of the Galway Film Fleadh – makes for a memorable and haunting viewing experience.

When it came to preparing for his role, did Boon explore the possibility that the intensely quiet and detached Tom might have a psychological condition?

“Phil and I had this conversation a lot of times, actually,” replies the affable actor. “It was something I was quite interested in from the offset. Early on, it became apparent that it wasn’t too important to delve into the specifics of what might be going in Tom’s head scientifically. He is so removed from reality – he doesn’t exist in the modern superficial world that most people his age do.

“That sort of thing wouldn’t be on his radar, and to be honest, his mum wouldn’t have looked into it either during his early education. So it was more about me and Phil together creating experiences that Tom’s had during his upbringing, which have made him the person he is. That was the approach, as opposed to actually identifying what psychological disorders he might be experiencing, whether it was depression or anything like that.”

Notably, both Boon and Murphy pull off flawless Leeds accents in the film. I mentioned that I developed a particular fascination for screen accents after viewing the TV series Chernobyl, which it turns out Anson auditioned for. The creative team made the decision that, rather than having a blanket Russian accent, the cast would speak English in their various accents. It was an intriguing choice that didn’t detract from the power of the show.

Anson confirms that he is keen student of accents.

“I did really work on it, because I just think it’s so distracting when you don’t believe an actor’s accent,” he notes. “It’s nice to wear an accent – because for me, it’s like wearing a costume. Especially with a character like Tom who is so heavy, when you take your costume off, you often forget everything you’ve been through that day. It’s the same with the accent.”

He also took creative inspiration from some major actors he’d previously worked with.

“When I was offered the film, I’d just finished Blackbird,” explains Boon. “Working with actors like Kate Winslet and Susan Sarandon, the amount of prep they do really inspired me. I learned a lot of my process from them. But I did a lot of independent prep myself, and also, the best part of working with Phil was that we did so much of it together. It was such an amazing collaboration between me and him in building Tom. That’s part of the reason I loved working on the film so much.”

Anson notes he was already familiar with the work of his co-stars, no more so than McElhatton’s turn as Roose Bolton in Game Of Thrones.

“I was a huge fan,” he enthuses. “I’d seen Michael’s work before, and indeed all of the guys. I’d seen Charlie in Peaky Blinders and Emma in Sex Education. And I knew Charlie was in Love/Hate as well – when we were filming, all of the Irish crew were talking about it. I need to watch it: everybody goes on about it, so I really need to give it a go.”

As Boon’s appearance in 1917, it must have been a huge break landing a role in a Sam Mendes project.

“Well it’s funny, I was actually offered it and The Winter Lake on the same day. And I shot them at the same time! I was juggling both. It was such an interesting experience: one week I was on a multi-million dollar movie, and then I was going to Sligo to an independent set. But you know what? Both were equally as enjoyable. When 1917 came out, the reaction was incredible. Sam Mendes is just an absolute diamond to work with – he’s out of this world.

I’m so glad he got the recognition he deserves for it, because he worked so hard on that film. He’s so good with actors, and he did feel like a father figure when I was working with him. He’s got a son who’s about the age of all the young lads in the film. He’d come and have little chats and ask us how were getting on, and he’s very personal with his direction. And like Phil Sheerin, he loves collaboration with the actors.”

Finally, given that Anson is a confirmed Spurs fan, I have to ask about the team’s last-gasp Champions League semi-final win over Ajax last year – a new peak for the competition, in a season when it had already ascended to preposterous levels of melodrama.

“I was going absolutely crazy!” beams Anson. “I was filming at the time – I think I’d just got back from New York, and I was doing a bit on 1917 the week after. So I had these couple of nights, and I didn’t want to go to the pub or anything. I do normally go home and away, but obviously I couldn’t go to Amsterdam for the Ajax match, so I was just watching at home with my dad and brother.

“I remember my reaction being so crazy that my brother wouldn’t speak to me for a week afterwards. He was like, ‘That was so over the top!’ I’ll never forget the commentator calling out, ‘Jermaine Jenas is speechless! Absolutely speechless! Tottenham Hotspur are heading to the Champions League final.’ It gives me shivers just thinking about it.”