British Gas says it has spent �400m improving customer service

The consumer watchdog said complaints about British Gas in the six months to September were twice last year's total, while complaints about its rivals fell.

The top problems were inaccurate bills and the lack of response to enquiries.

British Gas said the service problems were a "temporary situation" and improvements had already been seen.

Investment

"We've been putting a new billing system into place this summer and training over 10,000 frontline staff, as well as recruiting 500 extra staff," a British Gas statement said.

Guide to how bills have risen

"This is part of a �400m investment we are making to transform the way we deal with customers.

"We are confident the investments in service being made will restore our position as one of the UK's top rated energy suppliers."

The Energywatch statistics are featured as part of an investigation by BBC One's Watchdog programme, to be shown on Tuesday night.

Energywatch said it received 15,433 complaints about British Gas in the six months to September, more than double the same period in 2005.

In contrast, complaints about EDF Energy, Powergen, nPower, Scottish and Southern Energy and Scottish Power had all decreased.

Lack of response

One of the most common problems was the lack of response to customer enquiries - British Gas says it tries to answer customers' calls within 60 seconds.

It's a question of caring Allan Asher, Energywatch

Watchdog got its researchers to ring four of British Gas's most common customer service numbers ten times each, calculating the waiting time from the time of dialling until the moment an operator answered in person.

It took an average of nine minutes for the calls to be answered, and on one occasion it was 47 minutes before anyone replied.

"Watchdog viewers have been exposing problems with British Gas for years - in fact the company has been on the programme more times than almost anyone else," said the programme's editor Rob Unsworth.

British Gas has lost two million customers over the past two years, leaving them with 10 million gas and five million electricity customers.

Energywatch said that in proportion to their share of the energy supply market, British Gas receives twice as many complaints as the next provider.

"Everyone loses from poor customer service - and it makes absolutely no business sense at all," said Allan Asher, chief executive of Energywatch.

"It's a question of caring."

Energywatch said it had alerted industry regulator Ofgem to the problems.