The North Water: Outlander and River City star Gary Lamont on his latest role

The five-part series, which began last night, is based on Ian McGuire's Man Booker Prize-longlisted novel of the same name about the crew of a 19th-century whaling ship plying a brutal trade among the ice floes.

It is powerful viewing. The making of The North Water brought its own myriad challenges. The cast and crew spent almost a month in the Arctic – setting sail from Svalbard in Norway – with the locations used believed to be the furthest north any TV drama has filmed.

Almost two years have passed since it was made, but Lamont, who plays whaler Webster, still describes it as a "pinch me" moment. He is thrilled to have worked with Andrew Haigh, who adapted and directed the drama, and joyfully recalls the many jaw-dropping experiences from the shoot.

"To get on set in the Arctic with all those ice floes and polar bears interrupting us – it was very surreal," he says. "Every single thing about it, you were like: 'What the hell is going on?'"

A scene from The North Water. Picture: Nick Wall/See-Saw Films/BBC

It is a long way – geographically and metaphorically – from Castlemilk in Glasgow where Lamont grew up. Fellow actor Colin Farrell, he says, hit the nail on the head when he talked about how life-affirming working on The North Water was.

"It was so far out of anybody's comfort zone," says Lamont. "Let's be honest, most of us guys in the crew are working class. We are probably the first people in our whole family lineage to have gone there, to have gone that far north and to have seen those sights.

"It is wilderness. It is complete adventure. That rung true for us all. Every single one of us knew how special it was and we embraced that."

Reaching the locations involved a two-day voyage north of Svalbard. The production brought with it an eclectic flotilla that included an icebreaker, an accommodation vessel and the wooden schooner viewers will see on screen as whaling ship the Volunteer.

Lamont laughs when asked about any specialist attire or training for the icy climes. "It was a whole operation to get up in the morning," he says. "I shared a cabin with Phil Hill-Pearson, who plays McKendrick. We have become like brothers now.

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"It was probably the end of the second week, heading into the third, and I swung my legs out of my cabin bed and thought: 'Och, God'. It was a mission to get ready before you even got your costume on. You had to put on two layers of thermals. We had heated thermals that were battery-operated."

Everyone was well looked after by the accompanying expert Arctic crew, he attests. "It was almost like school kids on a trip. You felt a sense of safety in that bubble."

Once shooting concluded each day, a bar opened on the observation deck of the accommodation ship – a Norwegian ferry – for two hours at night. Teetotallers Farrell and Graham hunkered down in their cabins watching TV. What did Lamont do?

"Some of the boys are in sobriety and everyone was up for supporting that," he says. "But you better believe that myself, Jack O'Connell and Phil Hill-Pearson were up there waiting for that bar to open.

"Phil and I, with our roles, we would have a few days where we were not needed to do much or were in the background. We were like a couple of lounge lizards up on the observation deck."

Actor Gary Lamont. Picture: Sidey Clark

Then there was the "polar plunge" where some hardy cast and crew members jumped into the icy water for an exhilarating dip. Did Lamont join them? "Did I hell," he shudders. "Absolutely not. I was terrified.

"Bearing in mind I come from Castlemilk, Glasgow, and now live in Notting Hill, West London, I have no awareness of polar bears. There was no polar bear orienteering for me.

"One of the Arctic crew had said to me that polar bears can swim underwater, holding their breath, for four miles. Every time we were out filming on those wee row boats, I was convinced I was going to get munched. I was going to get munched whole and that was how I ended.

"That day we'd had a particularly hairy moment out filming and they'd called 'cut'. I had already gone for a sneaky shower. I thought: 'I will stand and watch them all freeze to death.' But good on them. I grew up in Scotland, I don't need to feel any colder."

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When Lamont left River City in 2017, after eight years playing Robbie Fraser, his plan was to target more serious dramas. Does this role feel like the fulfilment of that dream?

"Completely," he says. "The thing with River City, because I started on the show when I was so young, it was never the case: 'Oh, I've had enough and need to move on.' I feel very grateful I had the opportunity and I'm still on great terms with everyone. I learned so much there.

"I think I could sense the way the world was moving, all these multi-platforms like Apple, Netflix and Amazon. There is so much great TV being made and I could sense that coming. I thought: 'If I don't do this now, then I might be living with some regrets about what could have been.'

"It was tough. I'd had eight years of not having to worry about anything. I took a gamble. It has paid off and I am very thankful."

After moving to London, he did a stint as a civil celebrant and officiated funerals. It was a hiatus, says Lamont, that he will always look back on with great fondness.

The cast of The North Water with Gary Lamont, second from left. Picture: Nick Wall/See-Saw Films/BBC

"After eight years of that intense goldfish bowl thing of living in Glasgow, to leave and get my anonymity back was actually liberating," he says. "I relished doing other things. A lot of people might think, 'Oh, you had to …' but no, I got the privilege. I might never get to do that again."

His hard work and self-belief paid off when Lamont joined the cast of Outlander last year playing Evan Lindsay, a former inmate of Ardsmuir Prison and a settler on Fraser's Ridge. He has since done two series of the hit TV show based on the best-selling books by Diana Gabaldon.

Outlander may have a global fandom but in typical fashion, Lamont is taking it all in his stride. "We call my wig 'Auntie Cathy' because I look so like my Auntie Cathy when I put it on," he jokes. "It is hilarious. I played a camp hairdresser and now I am riding on a horse and shooting people. Bizarre."

He has a few projects in the pipeline, including the film Boiling Point with Stephen Graham ("one continuous take, no cuts") which is due for release in November.

This month will see Lamont commence work on another movie, Silent Roar, set on Lewis. He is also in the cast for the forthcoming ITV crime drama Karen Pirie based on Val McDermid's novel The Distant Echo.

As we return to talking about The North Water, he touches on some special moments that will stay with him. Lamont recounts one sequence where, after the trials and tribulations of sailing north, the crew of the Volunteer find themselves amid the stillness of the Arctic.

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"What you see on the screen is exactly how I felt," he says. "We sailed through the night. I woke up in the morning, pulled back the wee porthole window and was literally like: 'Oh my God.'

"We all went upstairs with our jackets on. I have beautiful pictures. That stillness. The expansiveness of it. I think that is what I will remember. Watching it now, I am 50 per cent PTSD and 50 per cent longing to be back there to smell it and feel it. It is a real visceral response."

The North Water continues on BBC Two, Fridays, 9.30pm. Stream all episodes on BBC iPlayer now