BT may face legal action after it targeted Tiscali customers hinting that the ISP's future may be in doubt.

BT sent a letter to a number of consumers that use Tiscali or its associated ISPs such as Pipex and Nildram with the headline 'Tiscali chief plots sell-off'. It is thought the mailshot was designed to provoke concerns following the announcement that Tiscali plans to sell off it's UK broadband operation within the next two years.

"We can understand why you're wondering what might happen to your Tiscali broadband service. And because no one really knows the answer just yet, it could be a good time to look for an alternative broadband service," the letter says.

BT then details how those interested in switching ISP can apply for their MAC number from Tiscali.

ISPReview, which obtained a copy of the letter, said Tiscali is taking legal advice over the stunt.