The utility, whose British Gas unit is Britain's biggest household energy supplier, said on Thursday that customer churn had increased following increases in its domestic tariffs and that account numbers had dipped slightly since the start of the year to 15.9m.
Average residential gas consumption in the first 10 months of 2011 was 17 per cent lower than in the same period of last year while electricity use was down 3 percent. Business consumption, meanwhile fell 15 per cent for gas and 12 percent 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," the company said in a trading statement.
Overall Centrica predicted that full-year earnings would still grow relative to last year but said it was conducting a review to identify possible cost savings.