SCOTTISH Gas and its sister firm British Gas misleadingly claimed their price rises were "balanced out" by similar increases made by rivals, advertising watchdogs said yesterday.

Television adverts for the two firms, owned by Centrica, featured the stories of customers who were said to be untroubled by soaring bills, because other companies would be just as expensive.

In fact, customers would be likely to save money by switching to almost any other supplier, according to the Advertising Standards Authority (ASA).

One Scottish Gas advertisement featured an animated gas flame, called "Archie".

"Last year I heard that prices were going up," he said. "And I thought well, if we change, the other provider might change and put theirs up as well. So we just sat tight. The other provider did put their prices up, and I believe it's all balanced out."

British Gas ran similar adverts, prompting four complaints from viewers and one from competitor ScottishPower, which argued the ads wrongly implied that customers would not benefit by swapping suppliers.

Centrica said the adverts were designed to show customers that all suppliers had put up their prices and it was difficult for people to compare costs.

However, the ASA said it considered the customer's testimonial to be a factual claim that British Gas users were unlikely to be better off if they switched suppliers.

The authority checked the claims with Energywatch, the independent watchdog for gas and electricity consumers.

"Energywatch's figures showed that dual-fuel customers very often paid more for their energy by taking it from Scottish or British Gas than they did with any available competitor," the ASA said in a statement. "We therefore considered the ads misleadingly implied that customers were unlikely to save money by shopping around to compare prices."

The firm were ordered not to use the adverts again, which ran last November. That was before Centrica announced it would raise energy prices from March by 22 per cent.

Tim Wolfenden, of consumer website Uswitch, said: "British Gas has always been among the most expensive suppliers. While it may be true other suppliers were raising bills, they started from a lower position so it probably does pay to switch."

Calculations by uSwitch yesterday showed that a typical British Gas customer would pay GBP 923 a year for combined gas and electricity - GBP 89 more than the average standard rate among suppliers - and could save GBP 305 by switching to cheaper suppliers or better payment plans.

How the big firms compare

Company Annual Bill* British Gas GBP 923 npower GBP 838 Powergen GBP 821 Scottish & Southern Energy GBP 819 EDF Energy GBP 803 ScottishPower GBP 802 Average GBP 834 Cheapest Option** GBP 618

Data supplied by uSwitch.com and correct as of 12 April, 2006 *Based on a medium-usage customer paying by fixed monthly direct debit. **Medium-usage bill for the cheapest tariff, averaged across all regions.