Send an unsolicited e-mail and risk losing your car. Life just got tougher for computer spammers after one prolific e-mailer found his Porsche seized and given away over the internet as punishment.

A crackdown on individuals who deluge computer users with unwanted e-mail offers has paid dividends after America Online announced it had seized the assets of serial spammers.

Payback will arrive in the form of a 2002 Porsche Boxster S, obtained in a lawsuit against a man AOL estimates "made more than a million dollars from spamming".

The £40,000 car will be the grand prize in a week-long sweepstake open to AOL subscribers.

A winner selected at random will be taken to the company's headquarters in Virginia to pick up their prize. AOL has previously won cash judgments and destroyed computers used in spamming.

Randall Boe, AOL executive vice president, said the latest case "represents us moving beyond that to the toys, the fruits of spam. We'll take cars, houses, boats, whatever we can find and get a hold of".

Mr Boe refused to offer details about the spammer, citing confidentiality terms of the settlement. He would say only that the spammer was sued in April 2003 and that the car had California plates.

The two-door silver-grey metallic Porsche has 18,000 miles on the clock, a leather interior, 3.2-litre 250-horsepower engine, CD-player and top of the range sound system.

It was seized as part of five federal lawsuits in which AOL targeted individuals and companies accused of sending a combined 1 billion junk messages to AOL members, offering pornography, college degrees, cable television descramblers and other products.

Mr Boe said spammers have been forced to sell houses or other tangible assets. The cash seized normally goes to pay lawyers and develop anti-spam technology.

AOL took the Porsche because of its "symbolic value," Mr Boe said. "Here was a spammer who made some money fast. He bought himself a Porsche."

Mr Boe said he hoped the publicity would deter spammers, though he acknowledged it would not stop spam altogether.

Spam now accounts for more than half of all e-mail traffic and costs businesses millions of pounds each year by clogging up corporate inboxes.

Legislation which came into force in Britain last month means that it is now a criminal offence to send unwanted e-mail. Bill Gates has predicted an end to spam within two years with the help of technical solutions being developed by Microsoft.