What will Gromit think? Wallace loses heart to Helena

In recent years, she has been a poverty-stricken mother in Charlie and the Chocolate Factory and a primate in Planet of the Apes.

So perhaps the forthcoming film starring the animated favourites Wallace and Gromit is a return to aristocratic stereotyping. For Bonham Carter is the voice of Lady Tottington, with whom the hapless Wallace, played by Peter Sallis, falls hopelessly in love.

The long-awaited first full-length Wallace and Gromit film, The Curse of the Were-Rabbit, has just been completed by Aardman Animation, based in Bristol, on time for a scheduled opening at cinemas on 14 October.

It is one of the most eagerly awaited films of the autumn thanks to the Oscar-winning charm of the protagonists dreamt up by the animator Nick Park for a college project more than two decades ago.

The new story sees Wallace and his hound Gromit in a pest-control business, called Anti-Pesto. But they are presented with an enormous challenge from a beast which is destroying the town's vegetable plots.

Nick Park said: "This terrible beast-rabbit comes to town and Wallace and Gromit are called up to rid the town of this beast."

Lady Tottington is one of several new characters along with Victor Quartermaine, a bloodsports-loving cad, voiced by Ralph Fiennes, who is Wallace's rival for Lady Tottington's affections. The adventure includes a new Wallace invention, a mindomatic machine, and concludes with a fast-paced action sequence.

The film is backed by Steven Spielberg's DreamWorks company and has taken more than 30 animators the best part of two years to complete. One animator can produce three seconds of film on a good day.

Nag Vladermersky, director of the London International Animation Festival which opens at the Curzon Soho cinema on Tuesday, said there was no reason to think that a full-length Wallace and Gromit would not work. Aardman had succeeded in maintaining a distinctive "quirkiness" when it made its first feature-length film, Chicken Run, he said. "I don't think they lost out in terms of their own identity."

However, animators, some of whose work is being profiled in the forthcoming festival, were divided over the effect of Aardman, he said.

"A lot of people feel they just make stuff for kiddies and it's not challenging. But they have become a great British institution and have given lots of work to the animation industry. It is the only British studio that continually manages to make short independent films."

The first Wallace and Gromit adventure, A Grand Day Out, premiered in 1991 and was nominated for an Oscar. The Wrong Trousers followed in 1993, and A Close Shave a couple of years later, both of which won Oscars.