Bettany likes this increased complexity. "The characters aren't entirely bad or good," he says. "My character is an opportunist. Brendan's character wants to get his wife back; I want to get back to my wife and children. And unfortunately those objectives really clash."

In addition to the echoing sets, filming on location in Britain and Italy, and costumes made mostly of scratchy wool or skin-tight leather, the cast and crew have bravely tackled those two dreaded movie elements: children and animals.

"We've got great kids and great animals, actually," Bettany tells us. "We've had no problems with children - just Brendan really! Eliza Bennett is incredibly articulate and smart. She works a day like we work and then does her school work.

"And we have 20 ferrets that are really good at certain things. One's really stupid and just sits on my shoulder, and one is an attack ferret that runs up my arm and tries to get my ear, and then at the last moment they grab it and swap it for the dull ferret. We have so many ferrets!"

The ferret trainers are quick to point out that Bettany is exaggerating. There are only 12 ferrets, each with a specific skills including, yes, clinging to his shoulder, following him around or grabbing things and taking them to someone. In the film, the ferrets are playing pine martens, which means they must also wear tiny glued-on horns. And they have their own passports, complete with photos, so they can travel around Europe with the cast and crew. Presumably they'll have their SAG cards by now as well.

After playing with the ferrets for just a bit too long, we also get to meet a Westie named Pepper, one of three dogs who play Toto, a literary character who travels into our world. Pepper, who's been dyed a charcoal color to look like the Wizard of Oz character, performs his tricks with unusual enthusiasm. And it turns out that several other familiar characters may appear in Inkheart, including Mary Poppins, Scrooge, Huck Finn and Tom Sawyer, and a crocodile with a ticking clock in its stomach. Tinkerbell had to be cut due to copyright issues.

Even with all this going on, easily the most colorful person on set is Helen Mirren. Decked out in a mad-artist costume in a floppy fur coat, diva head-wrap and gigantic rings and baubles, she has a mischievous glint in her eye that makes us curious about her character. The scene they've just shot barely involves her - she just sits there, bound and gagged, reacting with her eyes. And she's clearly having a ball.

"In a way my particular character's story is about learning to live in the real world," she says, "albeit in the fantasy world of this wonderful film. So that's the classic costume and the turban - very exotic, bohemian, a woman who lives in the world of literature."

Her performance, of course, will take the character in a different direction than the book's more cold-hearted depiction. "She's not a nasty person, she's an unthinking person," Mirren says. "She's just in her own world, living completely in the imaginative world of books, literature and poetry rather than in the real world. You meet people like this - professors of literature or history who are so into their own world that they can't see out of it at all. And in being obsessed with their own world they become careless with the outside world. I think that's the story of Eleanor. It's not that she's closed off, she's just dreamy. She's perfectly capable of stepping over a child to say, 'Oh what a beautiful sunset! I'm going to write a poem about it.'"

At which point Softley interjects, "She's very funny in the role!"

"I hope so," says Mirren, with that devious twinkle.

We'll no doubt find out when Inkheart is released in cinemas in the UK this Friday and the US on 23rd January.