Telewest, the third-largest group, yesterday said it was in talks with rivals NTL and Cable & Wireless Communications about launching the service.
"There is the possibility of a separately-branded Internet service which would allow us to share costs, expertise and brands," said Charles Burdick, Telewest's finance director.
Like its rivals, Telewest is preparing to launch high-speed Internet services early next year. The service, to be carried over TV cables rather than phone wires, will connect users to the Internet up to 100 times faster than a normal phone line.
Telewest is negotiating a deal with At Home and Road Runner, the US Internet groups, to provide content for its Internet service.
The company is also understood to be close to naming a chief executive to replace Stephen Davidson, who left following the group's merger with General Cable this year. Telewest is thought to want a British national in the job.
Telewest reported that sales in the half to June grew by 25 per cent to pounds 226m. Earnings before interest, tax, depreciation and amortisation trebled to pounds 54.3m. But higher interest payments meant kept Telewest in the red, with a pre-tax loss of pounds 141.6m compared to a loss of pounds 142m the previous year. The shares jumped 7p to 160.5p.