Ewan McGregor bounds into a room at London’s chi-chi Corinthia with a cheeky agenda. “So let’s start with Star Wars, the Trainspotting film, Bond and then we can get to Our Kind of Traitor.” Blimey, he’s seen right through me. Just maybe, this wily Crieff native has been doing this for too long. Some 23 years in the business, with a list of Hollywood credits long than Obi-Wan’s lightsaber, McGregor is more than aware of what journalists “inevitably” want from their allotted time. 

Not that he can blame me. Geeks the world over salivated over his recent vocal cameo in JJ Abrams’ Star Wars: The Force Awakens, reprising his role of Kenobi from George Lucas’s maligned sci-fi prequels. Even bigger news is the much-hyped Trainspotting reunion as McGregor, director Danny Boyle and most of the cast of the original 1996 adaptation of Irvine Welsh’s novel prepare to start shooting the sequel this month in Edinburgh. And then there are those rumours that he may be in the running to play James Bond when Daniel Craig hangs up his tux.

It’s a lot to get through – not least as we’re here to talk about McGregor’s latest, Our Kind of Traitor. An adaptation of John le Carre’s 2010 novel, McGregor plays Perry Makepeace, an academic who gets embroiled with a garrulous Russian money-launderer named Dima (Stellan Skarsgard). Meeting while on holiday in Morocco with his lawyer wife (Naomie Harris), Perry is drawn in to Dima’s glamorous world only to discover the Russian needs his help: desperate to escape his criminal associates, he wants to bring his family to the UK.

While Perry and his spouse get dragged into a murky world involving the British intelligence services, it wasn’t the espionage that sucked McGregor in. “The attraction was the relationship that Perry has with his wife,” he says, referring to the couple’s marital struggles following his character’s infidelity. “I liked the relationship with Dima – that’s at the heart of the film and I liked that. But that relationship wouldn’t exist without the relationship he’s having with his wife.”

McGregor is warming to the topic as he rocks back on his seat. “The fact that he’s damaged their marriage, I thought it was a really fascinating place to start a movie from. Usually a story starts with a perfect marriage that falls apart and does or doesn’t get back together, but this one goes backwards and I think that appealed to me.” It is the perfect role for McGregor, who has played the Hitchcockian hero before in films such as Stay and Woody Allen’s Cassandra’s Dream. As the film’s director, Susanna White, puts it, “He has that everyman quality.”

Would McGregor ever help a man out in the way Perry assists Dima? “Yes, I do think so,” he nods, before proceeding to tell a lengthy anecdote – something he’s very good at – about an encounter in the Ukraine on his well-documented 2004 marathon motorcycle trip from London to New York with his friend Charley Boorman. The adventure, which became a bestselling book and hit TV show, Long Way Round, took them through central Europe, across Mongolia and Siberia, and into Canada and the US.

If McGregor took as many detours on his journey as he does in the story, he’d probably still be on the road. “Sorry,” he says, bashfully, “my answers are so long.” Some edited highlights, then: a policeman stops them for speeding, doesn’t issue a ticket, advises them against staying in the town hotel or “you’ll get nits” and tells them to be back in the same spot at six o’clock. Then McGregor realises he’s lost his wedding ring, rides a 160-mile round trip to look for it, but eventually finds it lodged in his luggage.

The cop picks them up then drops them at an appliance shop in a poverty-stricken town. “Outside looked like the cast from Goodfellas,” says McGregor. “All these guys in leather jackets – it was like an extras casting for a mob film. And as they parted, this guy walked through them – he had a black moustache. His name was Igor and he pointed to this black BMW and he jumped in the car and the policeman waved goodbye to us. So we were following this BMW because we were told to – and we were good boys, we do what we are told.”

Taken to Igor’s house, and warmly welcomed, it was only when others arrived that they realised they were in a “Mafia stronghold”, as McGregor puts it. “The first guy took his jacket off … I turned around, and this guy was huge. He was taking off his shoulder holster with his hand gun in there. And then another guy arrived and he took his gun off. And everyone arrived – I swear to God, a guy turned up in a three-piece pinstripe suit. I’m not joking.”

Still, McGregor confesses he was attracted to the garrulous Igor in the way Perry is to Dima. “I definitely got the sense was a very dangerous man. I’m sure there would be many things I would not approve of, or like, or have anything to do with. But I liked him. I met his wife and kids. And if he’d come to me and said, ‘My family will be killed unless you help me. Can you take this back home?’ I would’ve said, ‘Yes.’ I’m sure of it.”

He and Boorman made a second journey in 2007, from John o’ Groats to Cape Town, called Long Way Down, and they still intend to travel through South America. McGregor is 45 now and the father of four daughters. He has been married for more than 20 years to Eve Mavrakis, the French production designer he met on the set of Kavanagh QC. His eldest, Clara, is 20, and harbours ambitions of becoming a photographer. Esther is 14 and he and Eve have two adopted children, Jamiyan, 14, and Anouk, five.

Maybe it’s the Los Angeles sunshine – he and his family have lived there since 2009 – but he looks remarkably healthy. So much so, you suspect he has a portrait rotting away in an attic somewhere. He's dressed in a black jumper and jeans with a black scarf swept around his neck. His brown hair is perfectly groomed – thick, swept back and flecked with blond highlights. He’s so glowing, with clear icy-blue eyes and a chin brushed with stubble, it’s hard to believe he’ll be reprising his role of the emaciated junkie Renton later this month. 

It’s been 20 years since McGregor played the Leith heroin addict, a breakthrough role in a film that became a cultural phenomenon. At the time, McGregor was 25, a graduate of the Guildhall School of Music and Drama in London who had already made a name for himself in the BBC adaptation of Dennis Potter’s Lipstick on Your Collar and Boyle’s compelling Edinburgh-set thriller Shallow Grave. But after his third collaboration with Boyle, 1997’s A Life Less Ordinary, the partnership fell apart when the director cast Leonardo DiCaprio in his Alex Garland adaptation The Beach.

McGregor was vocal about his displeasure, being overlooked for a post-Titanic DiCaprio. “I was gutted,” he told Vanity Fair. “It’s been a kind of love affair between Danny and me for years. But now it is as if he is seeing somebody else.” The two haven’t worked together since (though whenever they meet, he says, it’s like seeing “an old lover”). Did he ever think this day would come? “Ten years ago, I didn’t think so,” he replies, “and I didn’t think so necessarily when I read the novel, Porno. But in the last four or five years, I changed my tune.”

Published in 2002, Welsh’s Trainspotting sequel, set 10 years on as Renton finally comes back to Scotland after an extended sojourn in Amsterdam, didn’t set the world alight as its predecessor did. But McGregor is effusive about the “really good” script penned by John Hodge (rumoured to only be loosely based on the Porno novel), the screenwriter who adapted Trainspotting. “Once we read that, none of us was in any doubt that it was something to do.”

Even so, Trainspotting was such an iconic moment in British film history it would be galling to trample on its memory. “I think if there was any doubt about it – you can never know 100 per cent – I don’t think any of us would’ve wanted to do it.” Tonally, it’ll be different, he says. “I don’t think we’re setting out to remake the film we made in the 1990s. I don’t think that’s our goal. In that respect it should be different and it will be, I think, and it's 20 years later.”

McGregor last worked in Scotland five years ago on the Glasgow-shot sci-fi Perfect Sense from David Mackenzie, who previously directed McGregor in one his finest films, the 2003 thriller Young Adam. “I do love working there,” he says. “It’s a really lovely sense of going home. And the crews are brilliant. On that film [Young Adam], I was lucky enough to be making something I thought was incredibly powerful. But I don’t know … I don’t get sent many scripts from there.”

The actor recently turned up at the New York premiere of Miles Ahead – in which he plays a reporter hounding jazz maestro Miles Davis for an interview – in a pair of tartan trousers. But what makes him feel Scottish when he goes home? “It’s to do with the land, the colours of the land and the smell of the landscape. That’s it. More than the people or the culture. It’s the countryside, the landscape itself, that makes you feel Scottish. It gives you that ultimate sense of belonging. When I’m there, I feel completely at home.”

The son of two teachers – his mother Carol taught at Crieff High School and his father Jim was a PE instructor – it was McGregor’s extended family that inspired him to act. His uncle is Denis Lawson, who famously played rebel pilot Wedge Antilles in the original Star Wars trilogy. At 16, McGregor left school to be a stage-hand at Perth Repertory Theatre before taking a foundation course in drama at Kirkcaldy College of Technology. Lawson even advised him before his audition – telling him to recall a time he’d been beaten up in Glasgow. 

While his uncle later directed him in a 1998 stage production of Little Malcolm and the Struggle Against the Eunuchs, now it’s McGregor’s turn. He’s wrapped American Pastoral, his feature debut, which he also stars in. The only time he went behind the camera before was for the 1999 anthology Tube Tales, directing a short movie set on the London underground. “I’m still very happy with mine,” he says, smiling. “I’m sort of easily pleased with my work. I’m not like many actors or directors who are tortured by their work and think it can be better.”

Adapted from a Philip Roth crime novel, American Pastoral stars McGregor as a Jewish businessman. So what brought him to this? “It chose me, in a way,” he says. “I wanted to direct for 15 years.” Cue another inordinately long story, recapping his history with failed projects. Brevity is not McGregor’s strong suit. “This is an enormous answer to a very straightforward question,” he says at one point.
Firstly, he tried to buy the rights to Alessandro Baricco’s novel Silk but backed out. “I got scared,” he says. “And I always regretted it – thinking, ‘I should’ve struck while the iron was hot.’ And I didn’t. I bottled it.” Later, he tried to bring the story of round-the-world sailor Donald Crowhurst to the screen. “He had four kids – I’ve got four kids – and he put his whole life’s investment in this adventure,” McGregor explains. But the project was already underway with Colin Firth in the lead.

“I didn’t want to direct for the sake of it,” he adds. “I didn’t want to do it so I could say I was a director, so I could be in charge. I’m not really like that as a person. I wanted to do it because I really wanted to experience the full creative arc of making a movie.” McGregor was part of the production company Natural Nylon alongside Jude Law and Sadie Frost – part of the so-called Primrose Hill set. He co-produced Nora, in which he played James Joyce, but nothing more.

Just as Natural Nylon folded, McGregor’s Hollywood career exploded. A-list directors like Ridley Scott (for war movie Black Hawk Down), Baz Luhrmann (musical Moulin Rouge!) and Roman Polanski (political satire The Ghost) came calling. Yet for all his success, McGregor felt hw was in a creative vacuum – perhaps from his fallout with Boyle, where he was integral to the team – which American Pastoral has finally filled. “I’ll always be very grateful,” he says, “because it’s been a life-changing experience for me.”

Oddly, it was just before his test screening for American Pastoral that McGregor finally saw The Force Awakens (Abrams only called him for his cameo weeks before the film came out). He had time to kill, the cinema gave him a free ticket and off he went. “I thought it was great,” he admits. “Like everybody, it took me back to the original three, which I liked very much. I thought it had what we would expect from a current action movie, which was different from what we expected from the movies in the 1970s.”

While the prequel trilogy he starred in drew scathing reviews, McGregor has been diplomatic enough not to trample on the whole Star Wars experience. So will he turn up in Episode VIII, which is currently shooting? “People talk about that. Am I going to be in the new ones? Is there any spin-off one? The answer to all of those questions is I have no idea. I don’t know. I haven’t been spoken to about any of that. I probably wouldn’t be allowed to tell you anyway, but I truthfully don’t know.”

Time is ticking and we don’t get on to those 007 rumours, despite McGregor’s prediction we would, but he recently told The Hollywood Reporter, “It would be quite cool to play Bond.” In the past, whether it’s Michael Bay’s atrocious blockbuster The Island or Steven Soderbergh’s pulsating CIA thriller Haywire, the actor has starred in action vehicles. But a second Scottish incarnation of Ian Fleming’s super-spy after the legend that is Sean Connery? McGregor certainly has the cojones to pull it off.

Our Kind of Traitor (15) is in cinemas now.