I think particularly Daniel [Radcliffe], he knows what he's doing. I'm sure he'll finish up a producer. He really realized what it was, knew the size of it. And it was gigantic, the biggest franchise [Harry Potter] in history.

I loved working with [ Lars Von Trier], but I've done two films before, so I was quite used to him.He's a man of incredible moods of course, but he's also a hugely perceptive man, and there's no getting away from that. And he's able to put that perception into something like film, so we're very lucky.

Also the wonderful thing about film, you can see light at the end of the tunnel. You did realize that it is going to come to an end at some stage.

It's quite interesting, looking back at the first one [film about Harry Potter], nobody knew whether or not it was going to be successful as a film. The books were of course already very successful, but that's happened before, where the books were successful and the films weren't at all. But it turned out that they were.

The big problem with literature is people tend to take the dialogue from the book, forgetting that everything that surrounds it is literate, therefore not knowing quite how to put that on screen.

A very, very impressive director, Tomas Alfredson. It's only his second film [ 'Tinker Tailor Soldier Spy'], but he's a real find.

Very, very broadly speaking, you can put directors into two areas: One for whom you work, and the other with whom you work. And I prefer the latter, for obvious reasons. It's a great relief to feel that you're working with someone rather than for someone. You don't feel that you're being tested, as it were.