The owner of British Gas said that after it raised its prices by as much as 18 per cent, account numbers had dropped since the start of the year to 15.9m.
The drop in account numbers, which one analyst put at close to 100,000, was also due partly to Centrica ending doorstep sales in response to pressure from consumer groups.
Centrica said average residential gas consumption was 17 per cent lower and electricity use was down three per cent in the 10 months to October. Business consumption fell 15 per cent for gas and 12 per cent for electricity.
“As a result of the unusually warm weather experienced in the UK in recent months, and the corresponding impact on consumption, it is currently anticipated that Centrica’s 2011 earnings may be marginally lower than current market expectations,” it said in a trading statement.
The company had been expected to report a full-year pre-tax profit of £2.3bn, according to a poll of analysts.
Centrica said that it still expected a profit increase relative to last year but did not specify by how much.
Deutsche Bank has said with price rises of 25 per cent by 2015, a quarter of the country could fall into fuel poverty.