The National Audit Office said on Friday that the telecommunications regulator, Oftel, needs to make more of an effort to increase consumer awareness that they could save money by switching phone suppliers.

A survey conducted by the office last September indicated that 68% of consumers had made no changes to the way they buy phone service in the last two years; a figure that the NAO evidently considers to be too high.

Sir John Bourn, head of the National Audit Office, explained: "It is hard for consumers to understand how to get a good deal for fixed-line telephones, and therefore many do not try. Oftel has been working to help raise awareness, but it needs to have a better understanding of why consumers behave the way they do and should also make it easier for them to compare the tariffs on offer, for example by building on its tariff comparison accreditation scheme."

The tariff comparison accreditation scheme, designed to help consumers determine whether they could save money by switching supplier, was introduced last month.

The news delighted BT's arch-rival Telewest, the second-biggest cable operator in Britain. The cable operator's managing director, Gavin Patterson, said: "BT's been laughing all the way to the bank for too long so we're delighted the NAO has raised the issue of alternative phone suppliers and the savings waiting for consumers prepared to ditch BT.

"Switching is now so simple and most households can keep their BT number with a cable phone line. Our clear tariffs make weighing up the benefits straightforward and we'd encourage bill payers to shop around and not accept paying over the odds."

The National Audit Office did however point out:

"The savings, if any, that consumers can make varies according to their circumstances - some of the bigger savings can be achieved by moving to a more appropriate package with their existing supplier. It is not, however, easy to identify which consumers can benefit and by how much. The report recommends that Oftel should continue developing its assessment of which consumers are losing out through a lack of information, to identify the opportunities for them to get more for their money."