CWC, which is 53 per cent owned by Cable & Wireless, has been locked in talks with Telewest about a merger for months, but the two sides have so far been unable to agree terms that would satisfy both their larger shareholders and bondholders who have a significant slice of capital tied in both groups.
CWC has been aware of NTL's desire not to be sidelined in the consolidation of the UK cable industry but has so far preferred to press ahead with its planned two-way deal with Telewest while leaving the door open to other parties to enter wider negotiations at a later date. But there have been signs in recent weeks that the patience of NTL's chief executive is running out.
NTL is now believed to be pushing for a side deal with CWC that would shut Telewest out completely. NTL yesterday refused to comment.
One source close to the CWC and Telewest talks said yesterday: "Everyone knows where we are supposed to get to but whether we get there this week or next year, nobody knows."
CWC has also received approaches from other parties, including France Telecom and Deutsche Telekom, the French and German telecoms groups, which are both looking for a way into the UK domestic telecoms market and have had considerable experience within their own domestic cable industries.
Hopes of a three-way deal were boosted in May when as a result of a series of cable industry deals in the United States, Bill Gates, the founder of Microsoft, the American software giant, emerged with a 30 per cent stake in Telewest to add to his 5 per cent stake in NTL.
Analysts have expressed concern that without an agreement soon, the cable companies will not be in a position to make the most of what, potentially, is a strong competitive position in battling with both BSkyB and ONdigital to sign up digital tv audiences.
NTL, which was formed out of the old independent television transmitter operation, has been in the spotlight recently because of talk that it may revive its interest in taking over Newcastle United, the football club, dropped after the Government vetoed the Sky takeover of Manchester United.