Internet service provider Tiscali on Tuesday rebuked demands by British music companies to reveal the names of some of its customers who allegedly used the network to share songs illegally.

The British Phonographic Industry trade group said on Monday it had "unequivocal" evidence about 17 of Tiscali's customers and 42 from fellow telecoms company Cable & Wireless (CW.L) to support its claims.

Tiscali, an Italy-based company with about 1.2 million broadband customers in Britain, said it had received only extracts of a screenshot of one of its customers and nothing to support the allegations against the 16 others.

"Further, you have provided no evidence of downloading taking place, nor have you provided evidence that the shared drive was connected by the relevant IP address at the relevant time," Tiscali wrote to the BPI in a letter, portions of which were provided to Reuters.

Tiscali requested more information about shared drives and added: "If you wish to establish that downloading is taking place, please also provide evidence of this."

It said it had contacted the one customer about whom it received partial evidence, and would suspend the account if it did not hear back from the customer within seven days, pending a BPI investigation that must also supply more information.

Tiscali insisted it would not disclose customer names without a court order.

The BPI said it would supply Tiscali with all the evidence requested, though added that what it already provided was the same it regularly has used in court to win previous cases against individual file-sharers.

"The overwhelming feeling we're getting from this letter is that they're willing to co-operate, and that's hugely encouraging," BPI spokesman Matt Phillips said.

As for the customer names, Phillips said the music companies have won attempts to disclose them in court in the past, and likely would do so again.

"It's more of a rubber-stamping exercise to get the names," he said.

The music industry's relationship with Internet service providers (ISPs) has grown uneasy as it tries to enlist them in a crusade against file-sharing, which has cut deeply into CD sales in recent years.

The U.S. music industry tried to force telecoms companies to reveal the names of their customers who were allegedly using file-sharing networks to share songs illegally, but it lost a legal battle to do so in 2004.

The International Federation of the Phonographic Industry, the global music trade group, has tried to push a "code of conduct" on ISPs that would have them install filtering technology, among other measures.

"ISPs should make concrete commitments to control infringements on their networks," the IFPI said earlier this year.

Tiscali said it does not support the use of its network to violate copyrights, and that it has co-operated in previous investigations and worked with music companies to develop legal online download services.

C&W said it would "take whatever steps are necessary to put the matter right," adding that existing policies for its Bulldog broadband Internet service meant any accounts used for illegal file-sharing would normally be closed.