Cillian Murphy scowls at him with a fierce determination, “I’m fine.” This is one of those moments where you realise the calibre of Murphy’s on-screen skills.

From his portrayal as the enigmatic physicist/astronaut in Danny Boyle’s Sunshine to the terrifying depiction of the Scarecrow in Christopher Nolan’s Batman reprisal, Murphy has given us a breath-taking catalogue of incredible performances on screen.

But we’re not talking to any of these characters today. We’re talking to a humble gentleman, a quiet family man who is more concerned with the intrusion of privacy on him and his family rather than the next step in his career. From his earnest beginnings with the cult indie hit Disco Pigs in 2001, he has steadily risen through the ranks, working with almost every important director out there.

Now, at almost forty years old, Murphy looks back on a body of work that would ordinarily be associated with the very heights of mega-stardom. But he is an actor who has never compromised integrity or shown more than a passing interest in the trappings of fame. A cherished rarity in today’s celebrity culture.

We enjoyed your latest film, In the Heart of The Sea. We couldn’t help but feel there was a strong theme of environmentalism in the movie?

No, there certainly wasn’t for me, although people have mentioned it. However, there is that thing of man versus nature. You see that face-off between Chris Hemsworth’s character Chase and the whale, and I think most people come down on the side of the whale, which is fair enough.

But I think it’s nice that there’s an ambiguity there. Clearly what these men did was an obscene thing, slaughtering whales; apparently, if you fuck with the ecosystem of the planet, there will be consequences. Although at the height of the whaling industry in Nantucket the number of whales that were killed was only a fraction of what happened in the twentieth century when it became mechanised.

There were so many environmental consequences of the whaling industry at this time, and clearly I see that as a human being, but I don’t think the film in any way was meant to have an explicit environmental message.

It’s interesting you say that because not so long ago we interviewed the head horticulturalist at the famed Kew Gardens, Carlos Magdalena, he walked us through the culling of whales at the turn of the century and the environmental collapse of the entire ecosystem that followed that not many people know about.

Yes, well having said that, people read different stuff into things, and I think that’s great. I’ve made plenty of films that were purporting to be mainstream entertainment but had other messages in them. I made this film Sunshine with Danny Boyle that was a big sci-fi blockbuster, but it had a lot of subtext in there about religion versus science, and even in some of the Batman movies with Chris Nolan, there are bigger ideas present. But what I don’t like to do as a performer is to say to the audience, if you haven’t got this message from the film then you haven’t understood it. You’re free to extrapolate what you wan

Speaking of environmentalism, I read that you once argued on an aeroplane with one of the CEO’s of Shell?

Yeah. Sometimes when you do a studio movie they’ll put you in first class on a plane, which of course is a lovely way to travel but then inevitably you’re with CEO’s or whatever and on this occasion, I was having a drink, and this thing happened. But at the end of it, I think we kind of resolved our differences. We were like, look, man, let’s agree to disagree, its okay. I mean what else could he do but defend his position? But it was just after that massive oil spill in the Gulf of Mexico, and he was clearly in the shit, and I was very. . . I’d had a few G&T’s. It was an interesting discussion.

How does a typical conversation with your agent play out? You’ve been in such a diverse range of films, so I’m interested to know how that discussion goes at the beginning of the process when you’ve just picked up a script. Is there a back and forth? Or do you say, “I want to do this, this looks good to me”?

When I was a younger actor, there was much more of a discussion because I was figuring things out and wasn’t quite sure of the business. Then as I got older and had more experience, I took control. But people forget how invaluable agents are. Everyone needs an agent.

As you get older, your body of work increases, so people start coming to you. That happens more and more, and it’s a nice feeling. You’ve got the body of work, and you’ve set up the flags that say, okay this is the sort of work I like to do. And from that hopefully, people will recognise if you might be interested in something or not. But for this film, it was about Ron Howard.

I love his movies, and he’s a tremendously nice man. I know it’s not the most significant part, but I liked the idea of going through this whole physical process, shooting it for real in the ocean. It appealed to me even though it doesn’t feel as if I’ve done something like this before. I said all this and my agent said, “Okay do it.” So it comes around like that. I have absolutely no strategy or plan whatsoever. It’s completely random, based on what interests me. I’ve never had that thought of – Oh if I do this film then it will get me to this place in my career.