British Gas customers were urged to give the company "a bloody nose" after owner Centrica banked record profits just days after increasing household energy bills by 22 per cent.
Consumer group Energy-watch advised customers to move to a cheaper supplier after Centrica posted an 11 per cent jump in operating profits to £1.51 billion for 2005.
The record results came just a week after the company inflicted its 17 million customers with a fourth inflation-busting rise in gas and electricity bills in two years.
But Centrica insisted the increases were not enough to cover soaring wholesale gas prices, which left British Gas with losses of £75 million in the second half of 2005.
Annual profits at British Gas were down 63 per cent from £242 million in 2004 to £90 million.
Energywatch chief executive Allan Asher said: "As a consumer I feel aggrieved when one week I hear of a 22 per cent price rise and the next I hear of high profits.
"Its profits may not be coming from its domestic business, but the announcement from Britain's most expensive supplier can only jar with consumers who may not be able to heat their homes properly.
"Over the past week millions of consumers will have sat down, trying to figure out how to cope with £1,000 energy bills.
"If they deserted British Gas in droves then not only would millions save money on energy bills but they would give British Gas a bloody nose by sending out the strongest possible message that consumers will not tolerate the never-ending cycle of high prices that we are now seeing."
Help the Aged said the higher bills, combined with increased water rates and council tax, meant that "many older people will be struggling now more than ever" against fuel poverty. Many more would be spending over ten per cent of their income on heating and power, it said.
Centrica became the fifth supplier to raise prices or announce new tariffs in 2006 when last week it said bills would go up 22 per cent on March 1 following a 63 per cent rise in the cost of wholesale gas.
Yesterday, it pointed out that while the cost of wholesale gas rose 43 per cent in 2005, bills went up by just 14.2 per cent.
Outgoing chairman Sir Roy Gardner said: "Despite the latest price rise, we are still shouldering some of the burden of high wholesale prices in 2006.
"British Gas as a stand-alone business would not survive."
Centrica will hand out rebates of £90 to more than 300,000 of its most vulnerable customers this year, but with the cost of wholesale gas up again this year, Sir Roy refused to rule out putting up bills once more.
"We hope we do not have to make any more price rises this year," he said. "We pitched the latest rises at a level where we think we can get through the year without a further increase, but you really never know what will happen next winter."
Sir Roy said 2006 would be "a very challenging year" for Centrica.
The improvement in group operating profits - up from £1.36 billion in 2004 - came from its operations in North America, its storage business and British Gas Services, which installs and maintains central heating systems.
Centrica said group profits after tax fell four per cent to £661 million after its tax burden rose a third from £547 million to £706 million last year - or 52 per cent of its total earnings.
British Gas rival EDF also announced its results and said its two energy bill increases in 2005 "had a very positive impact on revenues" and "almost entirely offset" the increase in costs. ..SUPL: