Tofield wasn't planning on making a series or even releasing "Cat Man Do" when he made the cartoon. It was just an exercise to teach himself Flash, an animation program widely used in commercials.

"As I was making up a project to help me learn, a kitten I'd just gotten named Hugh was jumping on my head and batting at my nose," Tofield said in a recent telephone interview from London. "I thought, 'I'll just animate that. I'll base it on cat movements and mannerisms with a gag at the end.' It was just a little exercise to learn the program."

While he was in film school, Tofield largely taught himself animation by drawing flip books. He uses Flash to replicate the feel of traditionally drawn animation, although the component drawings are done with a digital tablet and pen.

When a Tandem client asked to post "Cat Man Do" on its website to test its Internet service in the U.S., the client was stunned to get 60,000 hits over two nights -- which nearly crashed the server. More than 50 people posted the film on YouTube under various titles.

Tofield seems a bit surprised by the success of the films that began as a simple technical exercise. He attributes a lot of the popularity to the believable personality of his feline character, which is based on firsthand observation. "I have three cats -- Hugh, Maisie and Jess -- and they've all contributed to the films and the book," he says. "The good thing about having three cats is that if one is sleeping all day, there are two more to watch and they're always doing funny things."

The popularity of the films led to offers to do a book, something Tofield had dreamed of since he was a boy in Bedfordshire.