A Colombian court has thrown out legal attempts by Net Registrar, the UK operator of the .uk.co domain names, to reactivate thousands of websites that have vanished from the internet.

On Monday morning, domain name administrator the University de los Andes shut down the domains, leaving an estimated 8,000 people and companies in the UK with websites and domain names that cannot be accessed.

In response, Net Registrar applied for an injunction against the move, which the court refused. The reseller now says it will appeal.

Robert Fox, Net Registrar's managing director, told vnunet.com that the university's move was an "unmitigated disaster" for both his company and its customers.

"We are flabbergasted and don't know what is going on. We have just heard they have rejected our claim but we will appeal," he said.

Trouble has been brewing for some time. In July 2002, the Colombian government ordered its Ministry of Communications to take over the administration of .co top level domain names from the University de los Andes by 31 December 2003.

Net Registrar said it attempted to contact the university to seek assurances that the domain names were safe.

But the university has blamed Net Registrar. In a statement on the www.uk.co website, it claimed that it gave the company the chance to sign a short-term contract.

"We offered to enter into a new arrangement with Net Registrar in order to safeguard your uk.co registrations ... for a short period of time to allow you sufficient time to transition to alternative domain names," it said. "Net Registrar failed to agree the terms of that new arrangement."

Fox said: "We couldn't sign the new contract put forward by the university because it gave them the right to close the .uk.co domain at anytime.

"But, even with a new operator replacing ourselves, the domain names should have been safe. Their action makes no sense."

The news has also shocked domain name resellers that have registered .uk.co names through Net Registrar for customers.

Nathan Dickman, head of e-commerce at domain name reseller www.unidentified.co.uk, warned that the future for holders of .uk.co addresses is uncertain.

"As there is no telling if these domain names will ever be rescued, people will have to pay to re-register another name to continue business," he said.