This was a chance to do something very different, seeing the world through the eyes of someone who's falling apart mentally 
Welshman Marc Evans cut his teeth on TV drama before making his mark on the British film industry with House Of America (1997), about a Welsh lad who falls foul of the American dream. After that came controversy with Resurrection Man (1998), a thriller set amid sectarian violence in Northern Ireland. But it wasn't until last year's Big Brother-inspired horror My Little Eye that he made a significant dent at the box office. His latest, Trauma, starring Colin Firth and Mena Suvari, is also a horror story but with a distinctly psychological bent.
Trauma is very uncomfortable to watch. Are you worried about the way audiences will receive it?
Well, that's the danger with this kind of film. You want to make it intriguing and odd and all that stuff, but you don't want to alienate the audience. I suppose, basically, you have to make sure that it doesn't put people off too much. But I think people will accept a weird film if they know it's going to be a weird film.
You've developed a reputation for dark films, even earning the nickname Dark Marc...
Yeah, that's Tommy Flanagan [actor and friend] who called me that! I suppose what it is - weird though it may sound - you don't choose your films in a strategic or career-minded way. You just find stories that interest you and some get made and some don't. So there is this haphazard element to it. The other thing is, I'm not really interested in making naturalistic films. And if you're not doing slice-of-life type movies, you've got to look at areas where you can play around a bit. The thing about a horror film or a psychological thriller is that it's expected to be original and odd in the way that you deal with the storytelling. Like with My Little Eye, the idea of telling a story with webcams was as interesting to me as the story itself.
What was it about this story that got your creative juices flowing?
I was very interested in the fact that it's actually about Colin Firth's character. He is in every scene so it's about his world and what's underlying his world, it's a very subjective type of film. It's not true to say it's totally from his point of view, but the world we're presenting is the world as he sees it. I had just done a film where it was all about an objective point of view - My Little Eye was about being a voyeur - and this was a chance to do something very different, seeing the world through the eyes of someone who's falling apart mentally.
As far as the story is concerned, I was interested in the kind of character that you might sit opposite on the Tube in London - where you see something in his eyes that disturbs you but you can always get off at the next stop. It seems to me that London is such a big, dirty city in that respect - full of these people who live in bedsits or flats, who would probably be OK if they lived in a more caring environment.
Do you have to be an outsider to pick up on that London vibe?
I don't know, maybe. But coming from the outside also made London a very exciting place to be, so it's not that I'm down on London particularly. I think it's just about getting older, when you're not only seeing that optimistic side of the city - where it's all about the thrill of the hurly burly - but also that downside where someone like Ben (Colin Firth) can slip through the cracks. I know it's a very melancholic sort of theme but it's an interesting thing for me to elevate that character and make him the hero - or anti-hero - of his world.
This is a very different role from the suave characters that we've come to associate with Colin Firth. Why did you cast him?
The thing with Colin was that I did a television job with him about ten years ago now, one of those bog-standard Ruth Rendell things, and they call her stuff "why dunnit" rather than "whodunit" because it's very psychological and full of dark characters. I remembered how good he was in that and, because he's in every scene, I needed someone who's sympathetic enough that the audience wouldn't mind spending so much time with him - and Colin is that actor. He's got an integrity but also a mystery about him.
Actually we had a conversation and Colin said, "Isn't it interesting how people never make films about a man in a suit anymore?", like the Hitchcock films with someone in his 40s or 50s thrown into a deadly situation. In a way that slightly older Everyman, as opposed to the 20-year-old hero, is something we don't do much in Britain anymore. So in a way, although Ben isn't really that ordinary man, we thought it would be a chance to do that film.
Wasn't the part originally written for someone younger?
Yes, but only because the writer [Richard Smith] is only about 24 so he's inclined to write about someone who's his own age. That would have worked in one way, but there's something more melancholy about someone who's a bit older, I think, because he's had bit of rough and tumble in his life, you know? That litany of wrong turns is the tragedy of the common man.
You've also cast Mena Suvari in a role that's very different to everything else she's done...
Yeah, it is an interesting choice. But I think Charlotte had to be angelic and have a lightness about her for us to be able to fall into Ben's idea that possibly she might be an entity. And she's just incandescent, she's one of those actors who does very little but brings a lot. It's like she has this ethereal otherness. She's got that down.
What do you hope that people ultimately take away from watching this film?
I'm hoping that they enjoy its ambiguities rather than get frustrated by them. I think this is the type of film that will lead to a really interesting and heated conversation in the pub afterwards. Genre films are really good when they can do that - if you can have an argument with your mate about it afterwards, that's getting value for money!
