It’s a very intense scene. Harry's so out of his depth, he's emotionally pretty much destroyed by this point and given up all hope. We're the French Resistance and Voldemort and the Death Eaters are the Nazis. Obviously, in a magical context. Harry's like a Vietnam veteran . He's seen awful things and come back into a society that's rejected him. That's the main parallel I've been drawing on.

He was perfect for this. I don't know if he could have directed any of the other ones. This was his story to tell. He's quiet, thoughtful, sensitive. Mike [Newell, director of Goblet of Fire] would sit in his chair and yell at us, or stand up and just be very loud and British. Whereas David will think for a bit, he'll come over, speak a few words, keep it to a minimum. The thing that always comes up with David is finding truth in the characters, truth in the performance, make it real.

So rather than just point the wand, there's a language in place, to make it feel as real as we could.

I know Alfonso (Cuaron, director of Prisoner of Azkaban) and Mike, when they came out, they were kind of shredded, but I've come out feeling invigorated. And I don't think I'm quite done with this world yet. These can be great films about childhood. The next one's full of sexual politics, and the kids are getting better as actors, and I want to push them even more. This one's quite lyrical and intense. The next one is more fun. I've had more fun in the last two years than I've had making anything. The whole thing's slightly addictive. It's difficult to let go.