UK graffiti artist Banksy has created a controversial title sequence for long-running US animation The Simpsons.

The intro, which was shown in the US on Sunday, opens with the street artist's tag scrawled across the town of Springfield.

It closes with a minute-long sequence showing dozens of sweatshop workers in a warehouse painting cartoon cells and making Simpsons merchandise.

The episode, called MoneyBart, will be shown in the UK on 21 October.

It is the first time an artist has been invited to storyboard part of the show.

The extended sequence was apparently inspired by reports the show outsources the bulk of their animation to a company in South Korea.

Delays and disputes

It features Bart Simpson with his face covered as he writes all over his classroom walls.

While in the sweatshop, kittens are thrown into a wood chipper so their fur can be used to stuff Bart Simpson dolls and a chained unicorn is used to punch holes in Simpsons DVDs.

According to the street artist, his storyboard led to delays, disputes over broadcast standards and a threatened walk out by the animation department.

"This is what you get when you outsource," joked The Simpsons executive producer Al Jean.

Other famous Britons to have contributed to the show include Tony Blair, Simon Cowell and Ricky Gervais.

Gervais also wrote Homer Simpson, This Is Your Wife in 2006, and is to make another appearance on the show next year.