They were Darth Vader's feared henchmen and some of the most recognisable figures in cinematic history. Now the imperial stormtroopers of the Star Wars films are at the centre of a new epic battle.

The British prop designer who created their famous white helmets and body armour is being sued by director George Lucas for £10m in a case starting at the high court tomorrow. Andrew Ainsworth was sued by the director's company, Lucasfilm, after reproducing the outfits from the original moulds and selling them for up to £1,800 each .

Ainsworth is countersuing Lucasfilm for a share of the £6bn merchandising revenue generated since the first film in the series premiered in 1977. The row centres on who actually owns the copyright to the stormtrooper uniforms.

Ainswoth said: "As far as I am concerned I am the original maker and I'm using the original moulds."

The prop designer was recruited to design the outfits in 1976 and sold the firsts 50 helmets to Lucas for £35 each. But in 2004 he discovered one of the original helmets in a cupboard in his home in Twickenham, south-west London and began to manufacture the uniforms.

A message on his website said: "Now's your chance to own your own piece of movie history."

A California court has already ruled in favour of Lucas who was awarded £10m in damages. But because Ainsworth lives in Britain Lucas needs the high court in London to enforce the order.

A spokesman for Lucas Licensing said: "We would never want to discourage fans from showcasing their enthusiasm for the movies. However, anyone who tried to profit from using our copyrights and trademarks without authorisation ... we will go after them."