There's a morality... I think there's a moral compass but whether that comes from religion or just from being a good person, and where one starts and the other begins... I'm a good person, I hope. But I'm never as good as I want to be, never as nice as I want to be, never as generous as I want to be.

I think doing different accents is part of the job of acting, really. It's something else that I quite enjoy the challenge of, to be honest.

Getting the call to be in The Goblet of Fire was like being welcomed into the most exclusive upper circle of some elite actors' club. You sit on set with the cream of the National Theatre and the RSC, all clutching wands or wearing witches' hats.

When you're playing a real person there's a balance between playing the person in the script and playing the person as he was in life. You have to be respectful and true to who that person was, but at the same time tell the story in the film.

All roads seem to have come back to Doctor Who in our life. But, no, it was a huge part of my growing up. I was a massive fan and it certainly inspired me to get into acting and to be ... one of those people that tells stories on TV. That was a huge part of my childhood.

Moths are the ones that freak me out. It's something to do with the way that, if they get squashed, they turn to dust. There's something very wrong about that. It all feels a bit Gothic.

I still am a geek, I don't think there's anything wrong with it. I see no shame in having an unhealthy obsession with something.