The phrase you usually hear after a cut is "That was great. Perhaps we could have another go. Maybe try it this way." Even that much direction is prefaced with a lot of praise and encouragement. It's quite like how you deal with toddlers: positive reinforcement, and then a little suggestion that you might want to try something different. Roman Polanski will stop the take and shout, "No, no, no!" Which is somewhat alarming the first time it happens.

I wanted to play a TV detective because it's a rite of passage; I wanted to experience every area of acting. I haven't done comedy or as much Shakespeare as I had intended.

My agents were like "Come to L.A., we've got meetings for you." I was like "No, I'm doing this now." Then my father became very ill back in England, and I didn't want to be away. I went back to England and did a bunch of crazy indie movies, all of which I loved with a passion, and none of which did any business.

I was lucky, because Ewan McGregor had already been shooting with Roman Polanski for about a month before I got role. And he did a faultless impersonation of what it was going to be like. So when direction happened, it was like, "Oh yeah. That's what Ewan said was going to happen." And so it was a little bit less debilitating than it might have been.

That was a bizarre and unlikely event, which has misled a generation of drama students from my old drama school that dreams really do come true. I was an unemployed actor. I had been an actor for about eight years, and had worked in theater, and done a tiny bit of TV, and somehow an audition video of mine ended up on Kevin Costner's television screen, and he rang me up and invited me to fly first-class to Hollywood and be in his movie The Postman.

Carey Mulligan is completely self-possessed. She knows what she's doing, and again, quite like the big-hitters I was talking about, my job was just to feel and reflect back the amazing performance coming my way. If anything, I was slightly pathetically flying in her tailwind. She's an extraordinary actress.

My parents taught me everything and set me up for life. I owe to them all the things I'm passionate about: music, art, the people I love, my career and family life, the fact that I have children and the way that I raise them.