Filmmaker George Lucas. (THE ASSOCIATED PRESS/Winslow Townson)

LONDON - The George Lucas empire struck back Tuesday against a British prop designer who sold replicas of the iconic Stormtrooper uniforms from the "Star Wars" movies.

Designer Andrew Ainsworth has fought a long legal battle against Lucasfilm Ltd., which sued him over the replica suits and helmets he sold through a Web site.

Ainsworth sculpted the Stormtrooper helmets for the first "Star Wars" movie in 1977 and later sold replicas of the moulded white uniforms, worn in the films by warriors of the evil Galactic Empire.

The case ended ambiguously at London's High Court last year. A judge ruled that Ainsworth had violated Lucas's U.S. copyright, but rejected a copyright claim against him under British law, saying the costumes were not works of art.

The judge also refused to enforce in Britain a US$20 million judgment Lucasfilm won against Ainsworth in a California court in 2006, saying Ainsworth's U.S. sales were not significant enough to make him susceptible to U.S. jurisdiction.

Now lawyers for Lucas want the Court of Appeal to rule that the suits are sculptures and therefore works of art covered by British copyright law.

Michael Bloch, Lucasfilm's lawyer, said the case rested on "the scope and meaning of sculpture" as defined by the law.

Bloch said the judge at the previous hearing "erred in holding that it is an essential requirement of every sculpture that it have artistic character, in that it must have, as part of its purpose, a visual appeal in the sense that it might be enjoyed for that purpose alone."

"On the erroneous approach of the learned judge, arguably the most famous sculpture in the world, Michelangelo's 'Pieta' in St. Peter's Basilica in Rome, would also be disqualified" - because its purpose is primarily religious.

The case is scheduled to last three days.