I can be prickly and difficult on set.

I wanted to be a police detective. In my work, particularly in documentaries, I am obsessed with finding things out, seeking ever-new facts and perspectives - each project can involve years of research.

I am happy to have now as Danny finally a more difficult role, in which I can shoot and fight.

For a film to be viable, it has to survive this process of scrutiny. I think most filmmakers have obsessive-compulsive tendencies and would be completely unemployable in any other job - so it's great to be able to channel your psychological anomalies into something productive and creative.

I love America, but I've now got two young kids and America has changed so much since 9/11 and Bush. It's beyond Orwellian. The idea in '1984' that if you keep saying you're being attacked then you can get away with anything has come true.

I remember from my school days Archimedes jumping into his bath and displacing water and coming up with his famous principle, and of course Isaac Newton being hit on the head with an apple. In other words, this realm of human knowledge - which is mathematical, essentially - can have a playful visual element to it.