The film of The Golden Compass is progressing very well. I spent yesterday at the studios in Shepperton, meeting some of the cast, including Sam Elliott, who's playing Lee Scoresby. Sam's resemblance to the Lee in my mind is just astonishing. His Lee has all the presence, the experience, the battered integrity, the humour, and the courage of the aeronaut who first walked into my story thirteen years ago. I can't imagine a better cast, and the sets and costumes are just astounding. They were filming the scene where Lyra approaches Iorek Byrnison at the gyptian camp and asks him to take her to the village near the lake, because the alethiometer has told her that there's something she needs to see there. Dakota had to speak to the empty air, because Iorek, of course, is being constructed pixel by pixel in a computer somewhere; but his voice is provided by Nonso Anozie, and a better bear you'd have to go a long way to find.

The set was constructed inside a vast sound stage, a building bigger than many aircraft hangars, and going all the way around the inside walls, from floor to distant ceiling, there was a truly enormous canvas painted with an Arctic panorama of icy mountains under a dark sky. The gyptian encampment was set up among great blocks of ice and snowdrifts - very convincing snow it was too - the tents and the firelight looking wonderfully real.