Telecoms companies are involved in a fixed-line price war

Existing Standard Rate users will move to BT Together Option 1, meaning higher line rental in return for cheap calls.

Up to nine million of BT's 19 million residential customers are currently on the Standard Rate scheme.

Industry experts and competitors are upset by the move, accusing BT of anti-competitive behaviour, as customers of rival firms will have to pay more.

This is because while their cost of renting the BT phone line will go up, at the same time because they use another provider to actually make their calls they will not in turn be able to benefit from BT's new lower call charges.

Ian El-Mokadem, managing director of One-Tel, said new companies wanted a "level-playing field".

Mr El-Mokadem told Radio 5's Wake up to Money programme: "At the moment if we go to BT wholesale and ask them for a line rental product so that we can charge customers whatever we like for line rental, they will not sell that product under the same terms...In fact, they charge us more per month than they charge BT retail."

But Gavin Patterson, BT's consumer managing director, denied the move - to start from 1 July - was unfair.

"It's a totally level playing field. BT retail pays exactly the same prices as any other service provider. With this move...we are cutting prices for the majority of our customers."

Call changes

Under the old standard rate structure, calls cost 1p per minute (local) and 3.95p per minute (national); under BT Together Option 1 users are charged 5.5p for an hour-long off-peak phone call nationwide.

In addition, daytime calls fall from 3.95p per minute (local) and 7.91p per minute (national) to a flat 3p per minute.

Uswitch, a website dedicated to calculating the cost of utilities, estimates that average phone users will save �24 per year by being moved from standard rate to BT Together Option 1.

However, 2.5 million people who currently rent their phone line from BT but buy calls from another supplier will not welcome higher monthly line rental charges.

New BT Together Option 1 charges Line rental �10.50 per month Evenings and weekends 5.5p for up to an hour per call, 1p per minute thereafter Daytime 3p per minute, 5p minimum call charges apply Source: BT (Standard rate customers are being migrated to Together Option 1 )

Monthly line rental is �10.50 under BT Together Option 1 compared to �9.50 under Standard Rate.

"For the bulk of phone users the changes are positive but for customers who rent their line but use another suppliers the news isn't so good," Jennifer Evans, Uswitch spokeswoman told BBC News Online.

"BT has been clever and made itself more price competitive, while at the same time making its competitors more expensive," Ms Evans added.

Price war

Standard rate charges Line rental �9.50 per month Weekday evening calls 3.9p per minute (national) 1p per minute (local) Weekend calls 1.5p per minute (national) 1p per minute (local) Daytime calls 7.91p per minute (national) 3.95p per minute (local) Source: Uswitch

uSwitch added that BT was still more expensive than the bulk of its rivals.

BT is fighting hard to hold on to its dominant position within the UK residential phone market.

At present, BT supplies 70% of UK homes.

Since BT announced its new pricing structure in March, 13 call providers have cut the cost of calls.

"There is a very aggressive price war taking place, with suppliers falling over themselves to cut the cost of calls. This is fantastic news for the consumer," Ms Evans said.