• L-R Ben Kingsley, Jake Gyllenhaal, Richard Coyle (still from Prince of Persia: The Sands of Time)
First Class protocol on the six am train south calls for hushed tones, delicate keyboard tapping, and the quiet enjoyment of endlessly replenished cups of tea. So I'm trying to keep the volume down on my chortling, but it's not easy.
Surfing the internet on my way to meet Richard Coyle – you'll remember him as Jeff in Coupling and Ben Graham in The Whistleblowers – I discover the daftness that is Rogue Nobleman, a little film from his student days.
"Oh, you have done your research," he says, in a voice as rich and mellow as the coffee in our cups. "It's a silly film I did with a friend of mine called Malf. I was at the Edinburgh Festival in the early 1990s, with my university drama group, and Malf came to visit. He brought his old cine-camera and we started taking footage around Edinburgh. We drove back in his beat up Ford Escort – the one in the movie. I have no idea how the film wound up on YouTube."
It climaxes with copious quantities of spew, I note. "That's what happens when you run out of inspiration at that age," he concedes. "We did Part Two a few years ago but haven't gotten around to editing it yet. It's just as silly, but with a lot less puking."
Coyle knows Scotland well. The 37-year-old builder's son – the second youngest of four boys – hails from Sheffield (ignore those persistent, inaccurate rumours that he's Welsh), and spent summer holidays camping in the Highlands.
"I love Scotland a lot. We used to go to Arisaig and Mallaig, that little stretch. My parents used to make it into an event. We'd put all the equipment into my dad's van, and make a bed, and set off on a Friday night, and stop briefly in a service station in the Lake District. We'd arrive at Crianlarich just as dawn was breaking. It was the most magical thing – and Glen Coe! Extraordinary isn't it? It's so unchanged and unspoiled that you can imagine the clans and the tribes living there."
He tells me this as we huddle under a heater outside a cafe tucked down an alley opposite the Donmar Warehouse, where he's appearing in Mark Haddon's first play, Polar Bears, with Jodhi May. Coyle's matinee is less than two hours away, but he's calm and unhurried. Which is just as well. His arresting blue eyes and Burton-esque voice, not to mention intelligence and unforced charm, make for a whole lot of magnetism. Suddenly I've a measure of his talent: he is the very antithesis of Coupling's Jeff.
At the end of this month you can see Coyle on telly as Moist Von Lipwig in Terry Pratchett's Going Postal. He heads a cast that reads like a Who's Who of British thesps, including Claire Foy, David Suchet, Charles Dance, Andrew Sachs, Timothy West, and Tamsin Greig.
"It's a great cast, and a brilliant adaptation of great source material. Pratchett is an amazing satirist. I think he gets put into a pigeon hole, because of Discworld, but he's kind of like a modern Charles Dickens who writes about the society we live in. They're richly complex books. Moist is a brilliant character and a joy to play – one of those jobs where I thought, 'I'm having the time of my life and don't want it to end..'
"The whole experience was magical. We filmed it in Budapest last summer. I'd been in LA for six or seven weeks, reading these great, economical, brilliantly produced American scripts. They're very very good, they write by committee and they've got it down to a fine art.
"My agent sent the Going Postal scripts from England and I remember sitting in the back bedroom of the house I was staying in. The French windows were open, the birds in the blue skies – beautiful. It's so golden in my memory. I opened the script and it went 'boompf!' It leapt off the page, crazy and full of magic and chaos. Compared to what I'd been reading, it was like a slap in the face. I said I've got to play this character!"
Part of the fun was throwing in lots of sly references to old films, by way of paying homage to one of his favourite art forms. And his actual favourite movie is? "I love all sorts. Regular guy movies, a popcorn movie. I think the first movie I ever saw was a Star Wars triple bill, when Return of the Jedi was released.
"Movies were a glorious escape. I remember seeing Jaws and Raiders of the Lost Ark, and my older brothers used to sit my younger brother and I down and make us watch horror movies like The Fog, or The Thing. They got off on terrifying us – we had nightmares for weeks."
Yet there was no lightbulb moment when he thought, 'I want to do that!' He went to York University as a politics student, and joined the drama society to keep busy. "Acting was never on my horizon. It was kind of a mistake. I was always the kid at the side of the playground, looking at the other kids. I didn't know how to get into the group. I was quiet and bookish, a bit of a geek. I was into orienteering when my friends were out clubbing."
Coyle researches his roles thoroughly and was once quoted saying it was harder building a film character than one for the stage. "Not harder, but very different," he interrupts. OK, but how much more difficult is it when you're working on a blockbuster like Prince of Persia, where there are endless green screen special effects?
"The question always has to be how do you find the tone of the piece. Once you can step through that door you've won half the battle. I play the crown prince, Jake Gyllenhaall's older brother. I'm about to inherit Persia, and I'm quite an ambiguous character.
"Details are important. It obviously starts with the script. There are films you can watch, there are books I can read, and this was a video game first. Because it's the same team that made the Pirates of the Caribbean films, I knew how it would be pitched, and once you get the tone it's quite easy to figure out what's required.
"Plus, when you're filming it, you're still working with actors. But you have to fill in the blanks of your imagination with certain things."
I found it mind-boggling that people complained Gemma Arterton wasn't pretty enough to play Princess Tamina. Coyle sighs, "You can never please everybody."
Prince of Persia was filmed at Pinewood and in Morocco, which was "great, but uncomfortably hot, especially with my wig, the heavy makeup, the robes, and riding a horse – it was like sitting on a radiator."
Coyle rode a bit as a kid, and acting on costume dramas, but for Prince of Persia he and his colleagues attended boot camp. "We met the horses that would be ours for the shoot, got to know them and did a lot of practise. Those who had ridden a lot were given quite intricate close quarter manoeuvres and stunts, like being able to make your horse fall down beneath you as if it's been cut down. I didn't get to use it in the film, but learning how was really fun. The horses are brilliantly trained. Some of what I did survived on screen – quite a lot of galloping and leading the army into battle."
Coyle has yet another film due out later this year, Reny Harlin's Georgia. "It's another great story, and based on real events. I play a cameraman and Rupert Friend plays a journalist. We're a team who go to cover the conflict in Georgia and get caught up in it. We get footage of an atrocity and it becomes a chase for us to get the footage out while being pursued by the militia. It's quite controversial subject matter, still.
"I literally got back from Budapest last September and the phone rang. My agent said Reny Harlin wants you to do it and you've got to be in Tbilisi in two days. And then Rupert Friend called me – he's been a great mate for years – and said, 'I'm doing it; come on, it'll be great, the two of us.' So I said 'I'm on a plane.'
"I didn't know what hit me. We landed in Georgia at about 4am on the only flight. I got about three hours' sleep then we were at the studio and they were throwing costumes on us and doing make up tests. We rehearsed, and Reny said, 'You've got an hour to get a quick shower and then we're having dinner with the president.'
"So we're at this table with the President of Georgia at a rooftop terrace restaurant overlooking all of Tbilisi, and we're a bit like, 'Huh, what's going on?' We found out they have a tradition at Georgian official dinners that all the men have to make a speech."
Really? And what on earth did you say? "Well, this is it. I said something about how we share a patron saint and a flag. I'd been there less than 24 hours and it was the only thing I'd really absorbed. I said something about common ground. We were all three sheets to the wind by then. We'd been drinking the local spirit – after every speech you have to toast."
Shaking his head, he continues: "Then they opened their equivalent of Alton Towers because we were with the president. It was around 1am and we're taking rides with the president, thinking, 'This is surreal.'"
All that food and booze. Was there mass re-enactment of the denouement of Rogue Nobleman? Coyle erupts with laughter. "Yeah! Some notables as well, chipping off to re-enact the final scenes behind trees."
It was Coyle's first encounter with Harlin, and one he won't soon forget. "He is probably the most natural born film maker I've ever worked with. He's incredibly warm and welcoming, with a huge appetite for life (that] is kind of infectious: you want to be in his orbit. To watch him on a set with thousands of extras – they'd given us the Georgian army and all their jets and choppers – and to see him co-ordinating not only extras in a land where he didn't speak the language, also the army and all their heavy-duty artillery, the cast, the crew; you've got to keep it all in your head.
"He knows exactly the shot he wants and how to get it. What an extraordinary thing to be able to do. He would never lose his temper. I thought he was a great captain."
Coyle admits he's "a terrible one for taking it home with me. I have trouble switching off when I'm doing a job."
If, as he once said, acting is his way of escaping the banalities of life, how does he reconcile himself to the mundane? "I'm wired when I come off stage, buzzing. I can't go straight to bed. So I tend to read or listen to music. Also my wife (actress Georgia Mackenzie] and I have a little daughter, 20 months old, so that helps. She's called Purdy and my world means nothing to her; she just wants her daddy there. You have to be really present with them, you can't get away with anything else. That's been brilliant, helping me to learn how to leave it at the front door."
Still, he's clearly a workaholic. "I'm better when I'm busy. I am happier. I am a bit useless when I'm not busy. I start thinking too much, which is never a good thing. When I'm busy I have a better perspective on what really matters, the priorities."
Just before we part I ask if he'd like to act opposite Georgia again – they haven't done so since meeting on the set of ITV's Up Rising. "I would love to," he says straightaway, "but those kind of opportunities very rarely come up. She's a brilliant, brilliant actress, and a great comic actress as well. I think comedy is the holy grail. It's the hardest thing to do. Period. I always wonder why there's not an Oscar for comedy. It's so hard to make people laugh. You can't fake it.
"The joyous thing about doing comedy is taking the truth, a tiny little thing, and amplifying it, thinking, 'How far can I take this to make it completely absurd yet utterly true?' Knowing where that line is and pushing and pushing it – that was one of the great things about doing Coupling and Going Postal. People think it's easy to do comedy and are more impressed by someone who can turn on the waterworks. But it's wonderful to make somebody laugh. To feel like you've touched somebody, anyway, is a wonderful feeling."
Prince of Persia (12a) is released next Friday; Going Postal is on Sky I and Sky HD on Sunday 30 and Monday 31 May at 6pm; Georgia is released later this year.
This article was first published in The Scotsman on 22 May.