In the modern art world, it will be billed as a rerun of David and Goliath. Damien Hirst has launched a legal battle to stop a struggling young British artist using his name on a "spoof" website.

The multimillionaire Hirst has employed the City law firm Manches LLP to act against Simon Phillips, a self-styled "internet artist" who owns the domain name www.damien-hirst.co.uk.

Hirst's legal team has submitted a dossier of evidence to the UK internet regulator Nominet, arguing that Phillips has breached his trademark and intellectual property rights. It claims that Phillips has committed an " abusive registration" with regard to both the name and contents of the website. The disputed domain name previously contained a potted history of Hirst's career, but now carries an image of a sailor dressed in red latex, with the slogan: "My arse is nothing to do with Damien Hirst."

Nominet, which has the power to transfer ownership of all domain names ending in ".uk", has given Phillips three weeks to submit his response to Hirst's dossier. It will then begin a process of mediation. A spokesman for Science, the company that handles Hirst's business affairs, said it had a legal obligation to act against all potential breaches of its trademark.

"We have to protect Damien's name, since it is a trademark. He has no problem with tribute sites, but the name of this one means that it could be confused with an official one."

Phillips, 25, promised to submit a robust rebuttal, accusing the founding father of BritArt of attempting to censor a colleague.

"I consider my internet site to be my artwork," he said. "It contains my comments on the state of the world, and since Damien Hirst is attempting to shut it down, he is guilty of trying to censor me.

"His lawyers have behaved in an incredibly heavy-handed manner. If they'd asked me nicely, they would have got a perfectly reasonable response. But instead, I was sent several very aggressive letters. I have therefore decided to fight this one all the way.

"I have nothing to lose, and would say to Damien Hirst that sites like mine are the way of the Web. If you don't like them, you can either ignore them, or set up your own, better one. It's a matter of principle that I am determined to defend."

For Hirst the stakes may be just as high. He is about to launch his first official website, containing a complete archive of his previous work, along with items of merchandise such as screen-savers.

Cristina Ruiz, editor of The Art Newspaper, said: "Perceived copyright infringement in the art world is not new. Many artists have been sued for alleged appropriation of ideas and images. These cases or threats, however, have tended to be brought by large corporations. What is unusual about this case is that the threat of legal action is coming from an artist."

A spokesman for Nominet said that Hirst's complaint was going through its disputes resolution service. In the event that no agreement is reached, both parties will retain the right to pursue the dispute through the court system.

Squatted

Tom Cruise

The Hollywood star took legal action against a cybersquatter and a judge for the World Intellectual Property Organisation (Wipo) found that the domain name tomcruise.com had been used "in bad faith".

Wayne Rooney

Even before Rooney's rise to fame in 2002, his name had been registered by a canny Welsh actor. Rooney was 16 when Huw Marshall registered waynerooney.com and waynerooney.co.uk. The case has been taken to Wipo.

Jeffrey Archer

The disgraced peer Jeffrey Archer recently found that jeffreyarcher.com was owned by a Canadian, Jeff Burgar, who bought the domain name eight years ago.

Bridget Riley

The artist only realised her name had been registered and was redirecting visitors to a site showing pictures of dismembered foetuses when the cybersquatter himself got in touch with her. Riley won her case.

Karen Yossman