It was the easiest research, just a lot of fun.

I've always been a believer in research. It's great to have an instinctual human reaction to a character, too, of course, but it has to be countered with knowledge and understanding.

I feel that I don't have to wait around for good scripts anymore, that I can get things moving more quickly. I can ring up directors I like and say I'm keen to work with them, which is pretty great.

I wanted to be an actor ever since I got on stage for the first time, aged 13. Before that, I thought I might follow in the medical footsteps of my parents: my father was a doctor, my mother a pharmacist.

I still have to say that I did 'Dirty Pretty Things' 11 years ago. That was a very sudden shift in my life and my relationship to my work, and it didn't feel it was impossible to make a film like that.

The idea of making a film - a film that I had certainly never seen before - about the slave experience was a huge responsibility. It's a project that requires a wider understanding of the geopolitical nature of the slave trade, of historical and modern-day racism.