Centrica is heading for more controversy over energy prices after the British Gas owner's interim profits jumped 65%.Earnings in the half-year to June rose to £886m from £537m on revenues of £11.7bn, barely changed from the previous year. Pre-tax profits rose from £448m to £2bn.A strong performance from its British Gas arm drove the improvement. British Gas' profits nearly doubled to £585m from £295m as margins rose from 6.7% to 13.2%. The impact of reduced retail prices was offset by lower commodity costs and higher volumes, despite it being one of the coldest winters on record. Centrica added 223,000 residential energy customer accounts after cutting its prices. "Centrica has performed well in the year to date, with strong results underpinned by improved operational performance in each area of our business. We have a sound platform for growth with significant optionality in our investment programme," chief executive Sam Laidlaw said.2010 results expected to be heavily weighted towards the first half and in line with current market expectations for the full year, he added.The interim dividend rises by 4.9% to 3.84p.