“I really don’t like guns,” declares actor Cillian Murphy. “I don’t get a kick out of them.”

The charmingly mild-mannered and intensely blue-eyed Corkonian might not be a gun freak, but the same most certainly cannot be said of Chris, the hardened IRA man he plays in High Rise director Ben Wheatley’s latest offering. Set in Boston in 1978, but shot entirely in an abandoned old Brighton newspaper building, the ultra-violent Free Fire has a very simple storyline. Two Irish freedom fighters (Murphy and Belfast actor Michael Smiley) meet with a not terribly bright criminal gang in a deserted warehouse to do an arms deal.

Egos clash, tempers flare and things escalate into pandemonium very, very quickly. With everyone present packing heat, and crates of machine guns and ammo lying around, the mother of all movie shootouts ensues. That’s about it, really. It’s a cartoonishly OTT action flick, its uncomplicated plot more than compensated for by the razor sharp Tarantinoesque dialogue and some great performances by a cast which includes Sam Riley, Brie Larson, Armie Hammer, Patrick Bergin and Jack Reynor. But we’ll get to the film in a moment.

Hot Press is meeting the star in a luxury suite in the Merrion Hotel midway through the Audi Dublin International Film Festival. Murphy didn’t have to travel very far to get here today. Having recently returned to Ireland with his artist wife, Yvonne McGuinness, and their two young sons after years of living in London, the family are now based in a grand Victorian terraced residence in Monkstown.

Are they enjoying being back on home turf?

“Tremendously so, yeah,” he nods, enthusiastically. “We were 14 years in London so we felt the time had come to come home. But I’ve made a few films and done a lot of theatre here, and our families are here, so we were always over and back. But it’s good to be home. The children are London kids – that’s the way they were headed. It’s nice, now, to see them become, totally by osmosis, little Irish boys. It’s really nice.”

Murphy recently turned 40, but looks easily a decade younger. He tells me that he’s feeling well rested having taken a few months break from work, but is soon to start shooting the fourth series of BBC period gangster drama Peaky Blinders. He has won widespread critical acclaim for his starring role as Thomas Shelby, the ruthless leader of the titular 1920s Birmingham criminal gang.

“Yeah, I’m about to go to start on the fourth series of Peaky Blinders next month,” he says. “So I’m sort of relishing the last of the freedom before I disappear into that. I did take a good bit off. I did a little film in Dublin before Christmas, and prior to that I had some time off. Because the year that we made this film, actually, I did three projects in a row, and it was a sort of an eight-month ordeal of working and being away. I love the work, but being away from home is hard.”

It’s not just the physical absence from his family; there’s also the emotional one.

“You’re away, but you also disappear into whatever character you’re portraying,” he explains. “So you’re absent as well in an emotional way, because you’re so involved in the piece. But the kids are at an age where it’s easier. They understand, they can rationalise it and they’re familiar with it. You do your best, like. I’ve had these chunks since before Christmas, so I’ve had from January until now to be at home, so you work it out.”

In terms of disappearing into character, does he switch off when the camera stops rolling? Or is he still in that mindset back in his hotel room? He shakes his head.

“No, I’ve never been that way, the method. I think that gets sort of over-used, or misused. For me, it’s whatever you need to do to get you to that place. Some people require different paths than others. I do find that it is quite immersive, depending on the role. It can be very, very immersive. And then naturally, it does take a bit of time to shake a character off. That’s why last year it was tricky, because you really shouldn’t back projects up one against the other. But, inevitably, timetabling can lead to that sometimes.”

In what order did they come?

“I did Free Fire, then I did this film called Anthropoid, then I shot the last series of Peaky Blinders, and it all went back-to-back. Funnily enough, this is the one that’s coming out last, even though we shot it first. That’s the quirks of distribution. But yeah, I don’t know how actors go on that sort of conveyor belt of work. I don’t ever want to repeat that again.”

What’s the most extreme thing he’s ever done to prepare for a role?

“It depends,” he says, shrugging. “It depends on how far away the character is from you physically, it depends on how far away the character is from you emotionally. You have to change how you look physically, you have to change your accent occasionally. You have a due diligence to immerse yourself in the environment that the character finds himself in.”

How did he prepare for the role of Chris in Free Fire?

“I just grew a moustache,” he deadpans, before bursting into laughter.

As it happened, Ben Wheatley wrote the role specifically for him.

“The sort of evolution of the project is that I met Ben four or five years ago after seeing Kill List in the cinema, and I immediately identified him as one of the most important young directors around,” he explains. “And I sort of chased him down and pestered him into going for a couple of pints with me. So we went for some pints, we chatted, and I said, ‘Look man, anything you have, I’d love to work with you because I think you’re really fantastic.’

“And he had this idea in his head about this film, so he wrote the part with me in mind. It’s a real gift when the director writes the part with you in mind, because you know he’s got your voice in his head. So basically, we decided Chris would be from Cork, where I’m from. Obviously it’s set in the ’70s. The thing that we did, all of us in this, is we shot off a fuckload of guns to kind of understand the power of them.”

Were they real guns?

“Yeah. Obviously not live rounds, it wasn’t a shooting range. I’ve done that in the past. I really don’t like guns, I don’t get a kick out of them. People go to America and they get a real kick out of going to a range or a shoot club. It frightens the shit out of me. But all of us needed to know how to handle guns for this film, so we did that. And Ben was very keen for us to realise that with ballistics and gun fights, the maddest things happen.”

Such as?

“People don’t just die, do one of those deaths (mocks receiving a gunshot) and they’re out (slumps over), the craziest things happen. Like you see in this film. People coming back to life, and it takes a long time to bleed out. This film is shot in real time, and you see the extent of what it means to bleed out. So we talked a lot about that. Me and Michael Smiley, who plays my partner in it, he’s from Belfast. Would’ve been around, grown up during the Troubles and all that. So we talked a lot about sort of their relationship, and the dynamic between the two of those guys.”

Free Fire was executive produced by the legendary Martin Scorsese. Was he present during the shoot?

“No, I’ve not met him. Ben has been to his house and hung out with him. He didn’t come to set, but he saw the movie and he loved it. Ben brought it over to show to him. You can see why they admire each other. You can see where they’re both in the same world. Ben is hugely influenced like all contemporary filmmakers are, but you can see why Scorsese has had this mentorship with him, because I think he sees something in him of himself, perhaps.”

Does Cillian Murphy have any mentor-like relationships in his own life?

“You know, when I was younger starting off, people like Brendan Gleeson, Stephen Rea and Liam Neeson were very encouraging and really took time with me,” he reflects. “I’ve become good pals with Stephen and Brendan. I haven’t seen Liam in a while because he doesn’t live here anymore. So those guys, and I would go to them for advice. I would call them up and ask them questions, because I admire them. Even before I was an actor, or before I had any desire to be an actor, I would have admired those guys.

“I’ve been an actor since I was 20, but I mean even before,” he continues. “I originally wanted to be a musician, but I had an interest in cinema and I would always go to see Brendan in his films. I would always go and see Stephen Rea and all the Neil Jordan films, and obviously Liam as well. I think every generation has people that they look up to, and we’re lucky in this country that we’ve produced such fine actors through the generations.”
Free Fire is in cinemas now.