Britain's top equity index retreated on Thursday from 15-year highs, with a drop in the share price of utility Centrica weighing on the market. The blue-chip FTSE 100 index, which had risen to a 15-year high of 6,921.32 points on Wednesday, fell 0.4 percent to 6,867.40 points in trading early in the session. Centrica was the worst-performing FTSE 100 stock in percentage terms, dropping by 7.6 percent. Weak energy prices hit Centrica's annual profits and the company also disappointed investors by cutting its dividend hard. "Centrica is another energy company that is suffering from a low oil price. Also, the fact that they've cut their dividend by such an amount will mean that some investors will now look elsewhere for better yields," said Dafydd Davies, partner at Charles Hanover Investments. Oil prices tumbled on Thursday as U.S. inventories were expected to hit record highs, which in turn put further pressure on energy stocks such as Tullow Oil and BP. BAE Systems also slipped after the company forecast only a modest rise in earnings for this year. Gold miners such as Randgold and Fresnillo rose on the back of a rally in the gold price. Investors also remained cautious due to lingering uncertainty over Greece. Greece is expected to ask on Thursday for an extension to its "loan agreement" with the euro zone as it risks running out of cash within weeks. It must overcome resistance from sceptical partners led by Germany. European stock markets had posted healthy gains earlier this week on optimism about a deal to extend Greece's loan agreement, and Logic Investments' Ryan Mitchell said any Greek loan deal could lift the FTSE to a record high of 7,000 points. "I'd still be looking to buy the market on the dip," he said. (Reuters) For more visit: www.businessworld.ie