Cillian Murphy on Oppenheimer, the Peaky Blinders movie and struggling with fame

He played Shelby in the popular, influential Peaky Blinders for six series and returns to 20th-century period drama to take on the title role of Oppenheimer in Christopher Nolan’s latest film. What the men have in common, Murphy tells me, is that they’re unusually contradictory. "I love the naughty, strange, weird, unpredictable areas of psychology that you get into where it doesn’t seem straightforward. They’re the best characters."

Alongside his cruelty, Shelby defends the oppressed and is traumatised from fighting in the First World War; Oppenheimer, having helped create the atom bomb, becomes deeply ambivalent about his role in history. "Chris [Nolan] used the expression that, in terms of his morality, Oppenheimer was always dancing between the raindrops," says Murphy. "That’s the stuff that I’m interested in – human behaviour and what pressure does to the human psyche."

It’s 21 years since Murphy’s major film debut in Danny Boyle’s 28 Days Later and, in his relationship with burgeoning fame, he has effected a similar dance. He’s been the star of huge international hits but chooses to live in Ireland rather than London or LA. His face – with distinctive pale blue eyes – is instantly recognisable around the world, but he hates being photographed by fans in public. "When I’m not working, I disconnect completely from the business. I need that. That’s the way I’ve always worked."

He prefers, he says, to let the work speak for itself. His roles have ranged from a transgender foundling in Neil Jordan’s Breakfast on Pluto and an Irish republican soldier in Ken Loach’s The Wind That Shakes the Barley, to the supervillain Scarecrow in three Nolan-directed Batman movies. Oppenheimer is Murphy’s sixth film with the director, but until now he was only cast in supporting roles. Does it feel that, after 18 years, Nolan has finally given him a job promotion?

Murphy laughs. "I’ve done my apprenticeship. I feel incredibly privileged to have worked with him all these years and it’s changed my life creatively and professionally, but I think he knew that I would love to play a lead for him. It just happened that this project came along and he felt I was right for it."

In fact, Nolan wrote the script for Oppenheimer with Murphy in mind, calling him "one of the great actors of his generation" – and the admiration is mutual. When Murphy got the screenplay, he considered it the best he’d ever read. "It was the ambition, scale, intelligence and profundity of it.

"Oppenheimer is one of the most notable figures of the 20th century, and Chris managed to distil the book [the film is based on American Prometheus by Kai Bird and Martin J Sherwin] into a screenplay that has elements of thriller and horror. It’s definitely not your run-of-the-mill biopic."

Taking on such a big role could have been daunting – but after working with Nolan for two decades, Murphy says they’ve developed a shorthand. "You get to a level where you really understand each other and there’s a trust. I used to play a lot of music and what I loved about music was the non-verbal communication you get when you’re playing with someone."

Indeed, before he aspired to acting, Murphy wanted to be a rock star. Born in 1976, the eldest of four children (with both parents working in education), he grew up in Ballintemple, Cork, as a music-obsessed teenager. It wasn’t long before he started making his own songs, playing guitar and singing in a band called Sons of Mr Green Genes (named after a Frank Zappa song).

"It was kind of jazz and early Pink Floyd," is how he describes their sound. "It was long, long songs with guitar solos." And they were good – in fact, the band were offered a multi-album deal by Acid Jazz records in the summer of 1996. The only reason we have "Cillian Murphy: actor" instead of "Cillian Murphy: Glastonbury headliner" is down to his parents, who vetoed the deal because they thought his brother, who was also in the band, was too young. "It was pretty devastating, but music is a young man’s game," he says. "The world isn’t lacking our music, so I feel like perhaps we did swerve something."

It’s a remarkably magnanimous outlook on what must have been a crushing disappointment – though, admittedly, Murphy’s quick swerve into an even more successful creative path probably helped soothe the pain.

The year before his music ambitions stalled, he had seen Cork theatre company Corcadorca’s production of A Clockwork Orange staged in a nightclub. "It was life-changing. It blew my mind and sowed a seed in my head about this other world of performance." In 1996 – the same year he met Yvonne McGuinness, whom he’d later marry and have two children with – Murphy was cast in Disco Pigs, a two-hander play written by a then-unknown Enda Walsh.

"Looking back," says Murphy, "that was a massive crossroads in my life." Disco Pigs was booked to run for a few weeks at an arts theatre in Cork, but was so successful it eventually transferred to Dublin, then to Edinburgh, London, Europe, Australia and North America. When Danny Boyle saw it and cast him in the film 28 Days Later, Murphy was on his way. And among those who noticed him in Boyle’s film was Nolan, who asked him to audition for the title role in Batman Begins.

He didn’t get to play the Caped Crusader (the role went to Christian Bale) but was cast to play Scarecrow in all three Batman films, and took supporting roles in Nolan’s Inception and Dunkirk. On the small screen, Murphy was catapulted to a new level of fame in the BBC’s Peaky Blinders, the stylishly violent historical drama about a criminal gang in Birmingham, first broadcast in 2013.

"It started off as a tiny show on a Sunday evening and it grew very slowly and without any hype, without any billboards, without any advertising campaign," he says. "It just grew because people told other people to watch it. I’m really proud that it has never plateaued and each series has become richer and stronger than the last. That’s a tribute to [writer and creator] Steven Knight."

Intriguingly, Knight was recently quoted in the press saying he had completed a script for a feature film version of Peaky Blinders – has he been in touch with Murphy? "That’s probably the worst thing about Peaky Blinders – getting asked about the movie all the time!" he laughs. "I would love to do a movie if there’s more story to tell. I’ll wait and see but I have no update for you on that."

It’s no surprise that Murphy gets frustrated with these sort of questions – after all, he’s famously wary of the press, which can make going into an interview with him daunting. But in conversation, he’s open, relaxed and funny, albeit frustrated by the superficiality and artificiality of most media encounters.

"I still struggle with the ancillary aspects of the entertainment business," he says. "There’s an assumption that you have to be a personality. I think that’s not fair, really. If your job is to disappear into character and portray a person, surely the sensible approach is to not to reveal too much of your own self.

"I’m loath to be one of those whingeing f***ing actors going, ‘Woe is me,’" he adds. I’m really lucky, happy with my life and, you know, that is part of the bargain. You do sell anonymity and you sell some level of privacy. And that’s what you have to live with. I’d love to just do the work and go home."

At least for today, he can. With our time over, Murphy can get back to real life – and keep dancing between the raindrops of superstardom.

Oppenheimer opens in UK cinemas on Friday 21st July. Check out more of our Film coverage or visit our TV Guide to see what's on tonight.

Try Radio Times magazine today and get 12 issues for only £1 with delivery to your home – subscribe now. For more from the biggest stars in TV, listen to The Radio Times Podcast.