Three children have become adults since a phone call with Jo Rowling, containing one small clue, persuaded me that there was more to Snape than an unchanging costume, and that even though only three of the books were out at that time, she held the entire massive but delicate narrative in the surest of hands.

Film has to be reflecting the world that we live in, and that's all you want to be a part of. Actors inhabit the same planet as everyone else. It's a weird thing that happens when you're an actor because people hold you up because you somehow embody in parts groups of people or people's hopes or something.

Who I am gets in the way of people looking innocently at the parts I play.

One of the most, in a weird way, encouraging things a director can say to an actor - I know this as an actor - is when you ask them a question, they say, I don't know - 'cause it means there's some space there for you to find out. And it means that there's going to be a process.

I have every sympathy for writers. It's a mystery to me what they do. I can edit. I can cross out and say, 'I'm not saying that' or, 'How about we move this to here? Wouldn't that make that bit of the story better?' But where any of it comes from is beyond me. I will never write a play or a novel.

All I want to see from an actor is the intensity and accuracy of their listening.

I think the thing about film is, as it gets proved by a lot of young filmmakers now, that the medium will just go on reinventing itself, and so you just hope to be a part of that and not a part of some kind of endless regurgitation or 'Here I am doing what you know I do' kind of thing.