NTL has admitted providing "unacceptable" levels of customer service. The cable company was targeted by the BBC's Watchdog consumer affairs programme this week, following the receipt of a further 1,700 complaints from its cable TV, broadband and telephony customers.

In a reply to the Watchdog website, NTL acknowledged that the "standard of service experienced by the customers featured on the programme is unacceptable".

But the company claims that out of its 3.3 million residential customers the number of complaints has been reduced to 0.31 per cent over the past four months.

It added that the number of complaints received directly by NTL fell by over 10 per cent during 2005.

"Last year we highlighted an investment of over £100m to replace a multiplicity of outdated facilities and systems. This ongoing programme of product and service enhancement continues and is our number one priority," said NTL.

Some 82 per cent of customers surveyed over the phone in December said that they were satisfied with the service they received, according to the cable firm.

"NTL is more customer focused now than at any point in its recent history," the company said.

"We will continue to place the customer at the centre of our business with real and sustained focus on areas that affect the customer experience, from answering the phone promptly to resolving complaints at the first time of asking."

NTL is set to become the uk's biggest cable provider when it merges with leading rival Telewest in a deal worth over £6bn.

The company has the potential to grow even further should the planned acquisition of MVNO Virgin Mobile go through.