The credibility of online auction sites has been called into question after the Millennium Dome appeared for sale on Yahoo!'s auction site.

Described as a "rather unusual property situated in a very attractive waterfront setting", the Dome was offered at a starting price of one pence. After one week bidding had risen to about £10,000.

Lloyd Shepherd, senior producer for Yahoo!, UK and Ireland, said customer care staff had spotted the ad, but decided that no action would be taken because it was clearly a joke.

However, when contacted by vnunet.com, Shepherd said the Internet service provider had decided to remove the auction and that the appearance of similar auctions "won't happen again".

"It's obviously a joke, but it is an abuse of the system," said Shepherd.

"We do monitor and check the auction site for items such as weapons and pornography, but this item was under other goods and services. Commercial property is not an area we would necessarily check as much."

He said that only 20 people had bid for the Dome, and the person responsible for the ad would be contacted by email.

"People using the site do rely on a certain level of seriousness. Anyone using the site should take note of the legal information and be sensible about it," he added.

Clive Savage, an analyst at researcher Fletcher Research, said joke auctions "diminish the value of the auction proposition".

"Look at Christies, no one auctions silly things there. They have set checks and criteria to meet," he said.