SOME TIME in 1998, doll designer Carter Bryant was driving past Kickapoo High School in Springfield, Missouri, when he had a revelation.

Bryant had worked for Mattel, maker of Barbie, the world’s bestselling doll. But with their short skirts and bad attitudes the girls he saw outside the school were more Britney than Barbie. He went home and made sketches that eventually became the controversial Bratz dolls loved by tweenage girls around the world.

This week, those sketches will take centre stage in a Californian court as Mattel tries to persuade a jury that it owns Bratz. The cat fight looks set to be ugly.

Bratz manufacturer MGA Entertainment believes Mattel wants to “litigate it to death”. In papers filed before the court, Mattel has admitted using private detectives to follow employees it suspected were spies and compiling a dossier on MGA boss Isaac Larian.

Bryant took his idea to MGA while he was working at Mattel. When Larian gave his approval to the project, Bryant left to dedicate himself full-time to the line. Since their launch in June 2001, the four original Bratz girls, Cloe, Sasha, Jade and Yasmin, with their big heads and short skirts, have badly hurt Barbie. Additional friends have been developed along with spin-off games, films and music.

More than 150m Bratz have been sold globally. Barbie sales declined 12% in America in the first quarter as competitors chewed away at its market share.

The court papers show Mattel knows it is in trouble. “The House is on Fire” became a catchphrase in Mattel internal presentations in 2004, often accompanied by a logo of a burning house. Documents refer to a “rival-led Barbie genocide”.

Barbie will be 50 next year. She’s on the internet and keeps changing jobs — in recent years she has been a presidential candidate, a swimming teacher and a vet — but those Bratz keep coming. Some psychologists have criticised Bratz dolls for their skimpy clothing and pouting looks but it hasn’t dented sales.

Mattel argues that Carter made his Bratz sketches while he was working for them. Though his fateful car ride past Kickapoo High came after he had left Mattel for a time, he rejoined not long afterwards and, Mattel argues, continued to work on the idea when he returned to Barbieland.

Mattel has had Bryant’s sketches analysed to date them and its forensic experts claim that analysis of the paper fibre and ink show that the pages are tied to a sketch pad Bryant used for Mattel projects.

MGA disputes those claims and says that Mattel has, in any case, left it too long to make a case. MGA argues that Mattel launched its suit only after Barbie’s sales started to slide.

Mattel has settled a separate legal action with Bryant who, Mattel claimed, made $30m (£15m) from a royalty agreement he had with MGA. As Tuesday’s court date looms, it seems unlikely that Barbie and the Bratz will kiss and make up.

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