The Senate Energy Committee has responded to growing public anger over record oil prices with an open letter to the US commodities regulator expressing concern over the fullness of the body's analysis and requesting more detail on the activities of speculators.

Jeff Bingaman, chairman of the Committee and author of the letter, said: "I remain concerned that the Commodity Futures Trading Commission’s assertions to date - discounting the potential role of speculation in driving up oil prices - have been based on a glaringly incomplete data set."