After so many years of working on the trilogy, what is the key to coping with the stress of it all?

One of the keys is that I love what I'm doing. I think that's important, psychologically I'm as happy as I could possibly be because I'm doing one of the great books of all time and I'm having all this fun with this great budget. It's practical stress I guess, just tiredness and exhaustion, but I'm used to being tired, I've been tired for four or five years now so I don't know any other way to be!

You are creating cinema history - do you ever allow that thought to enter your mind?

To a degree. One of the things I am very proud of is that we're making films that I think don't remind you of anyone else's films. They're not derivative, which a lot of cinema tends to be. So I'm pleased and happy with the way these films have created a style which doesn't remind you of any other films.

Lots of people theorise on what "The Lord of the Rings" is about... what do you want audiences coming away from the film to think about?

I think it's about a lot of things. Tolkien obviously had a bee in his bonnet about quite a few different subjects and he managed to get them into the story. We've tried to honour a lot of his themes. We made a promise to ourselves that we weren't going to put any of our own baggage into the films and so there's his environmental themes, themes about friendship, loss of freedom, slavery... so hopefully they just remind people of the books.

There are changes from the novels, though. What informs those decisions?

They come down to your instincts as a filmmaker; our main responsibility is to make an entertaining movie. There's also an awareness that the majority of people seeing the film have never read the books, so we had to walk the balance of trying to make them so fans would be able to experience an interpretation of the book, but at the same time they had to work for people who hadn't read the books. So changes we made tended to be done for the motivation of making it a more familiar film structure.

Have you allowed yourself to think about what you might do when it's all over?

I don't really want to split part of my mind off yet to other things. I want to be able to concentrate on "The Return of the King". I really want to end this thing with a bang. I want "The Return of the King" to be the best film. I think it will be, actually, so it's not quite the time yet to think about other things.