How did it all begin?
Terry Pratchett: Discworld began in the early 1980s, mainly I suppose it was initially an antidote to fantasy, what I call the "consensus fantasy" universe; the one with the wizards, witches, trolls, elves, dwarfs, healers and so-forth. So very well established by many authors. So, I thought, now it is time to have some fun, and the best way to have fun with the fantasy universe, is to take it seriously, and say how it would have worked if it was actually real? That was how it all began.

This is the first live action Discworld film? Others have been in the offing, what was it about this one that made you agree to it?
Terry Pratchett: Probably the biggest problem of filming Discworld is me. Discworld has made me quite a lot of money and I haven't got anything prove. I am not desperate for a movie. One would like one to happen, but it is not something I'm prepared to give up a lot for, infact I have bought back the rights of two Discworld books that I had previously sold to the cinema, because no progress was being made on either of them.

But, I have to say this one happened because Vadim and Rod came to see me. They were very, very enthusiastic. Now, enthusiasm is a debased coinage in filmmaking because everyone is always enthusiastic, you can take as a given they will tell you how enthusiastic they are about your book. The important thing is never to ask them a detailed question about it, because they won't know. But Vadim had got it, he was hugely enthusiastic, he was bouncing off the walls. But when I read his script, it worked, he had got it. When I made suggestions he listened to them, he incorporated them and all the way through the process I have been waiting for something to go wrong, you know tear off the mask and say "Ha ha ha haaaaaa. You didn't think it was really going to happen!" But no, it continued all the way through.

Can you tell me the main theme of the Hogfather?
Terry Pratchett: I think perhaps the main theme of the Hogfather is that our fantasies make us human. Is it a good thing that children believe in the Tooth Fairy, believe in the Hogfather, or, shall we say, Father Christmas? Yes, because if we are anything we are imaginative, and as I say in the book we need to train our imagination on the little lies - Tooth Fairy and the Hogfather - so then we can believe the big lies like justice, truth - and by taking them seriously make them into something that is real. Without our imagination we would be just another type of boring kind of ape.

Death is a very interesting character. He is the destroyer and the saviour of mankind. Can you talk about how you developed his character?
Terry Pratchett: Death doesn't kill people. People kill people. Old age kills people. Disease kills people. Death turns up afterwards. Indeed you can say that he is a great friend to those who are in pain for example. And one automatically thinks of him as caring about his job. Maybe it is just the way my mind works, because he spends so much time in the company of human beings and to him we are like may flies. We live a very short time and we waste most of it, he can't understand us. He says at one point during Hogfather that the human race has invented one of the various things that can be in the universe which is boredom. We live in this huge universe full of vast wonders and we get bored so very easily and we make up fresh things. He is simply fascinated with us, I mean he does his job and he will continue to do his job but you get the feeling he is in some way on our side.

Paula: How do you feel about seeing Discworld - that's been inside your head for last 20, 25 years - being brought to life?
Terry Pratchett: It is quite unnerving to come face to face with the character you have created; in fact, the first one that I saw was on the very first day when I met Death, figuratively speaking. He was exactly how I imagined him in the books and shaking his hand was an uncanny experience. And I thought there are not many people who, while still sane, apparently met and shook hands with the figments of their imagination.

Do you see parallels between that story and the process of making the film?
Terry Pratchett: It is fascinating for me to watch the movie emerge a bit at a time. I get to see rushes, I can more or less work out where everything goes and it is great to see it gradually come together, you get fresh surprises and I have to say many, many delights. One of the interesting things is that the budget for this movie has not been large. So the guys have had to make do with their ingenuity and ingenuity can do the work of money if you are ingenious.

How did you enjoy playing Toymaker?
Terry Pratchett: Well I think the role of Toymaker was to be terrified in the face of Death. I can assure you since that was the first time I have ever been in front of a movie camera I was terrified indeed. Especially since at one point Death managed to give me a thumbs up while the camera wasn't on which was a wee bit disconcerting.

When you go to the set, how do you feel?
Terry Pratchett: It is a terrible thing to admit but when I visit the set I think they are all working for me. You know, I thought "Well done lads, jolly good, yes we have a half holiday on Hogswatch". They are making a movie for me. Ok, a few million other people will see it as well which is very generous of me to allow them. But I know that's how I feel and that is a great feeling.

Will there be another one?
Terry Pratchett: Will there be another one? Amicable discussions being discussed - beyond that - there are a lot of, pressure is the wrong word, I think a lot of people have enjoyed themselves making Hogfather. So it is very natural at this time to say "Can we do it again?" You know, of course totally different, pick up another Discworld book. And it would be very nice to think that this could be arranged. But I have been in the business long enough to say "Yes, it is great fun", but sooner or later some guys probably wearing ties have actually got to sit down and talk about it. But I'd love to be another one.

Is there anything you would like to add?
Terry Pratchett: For various reasons I was quite suspicious for quite a long time into this process. Thinking it is too good to be true, and it can't possibly happen. I think the day when it suddenly came alive for me was a month or two ago, when I went to Angels, to be tried out for my costume and I was there for about an hour. They were really trying to get it right and I was ever so pleased especially with the shoes. The kind of shoes that Baldric out of Black Adder would have thrown away, they are absolutely marvellous and I thought this is really going to happen and they are taking it really seriously. Because this is a tiny, tiny little role, and they are taking it very seriously and it really is going to happen. They showed me the designs for the costumes and I realised the show was on the road.

It sounds as if Vadim has restored your belief in filmmaking?
Terry Pratchett: One of the things that has impressed me is that this movie have been made fast. And I don't just mean the shooting that seems to be absolutely going along as if it was on a bullet train. But I think we started talking back in the middle of the summer last year. And here, as I speak to you; we are a few weeks away from the wrap party. Things happened incredibly quickly.