Speaking to the Today programme, Mr Clare indicated that gas prices will continue to rise in 2006.
"I don't think anyone forecast the extent and the degree to which wholesale prices increased and unfortunately if we look at the wholesale price forecast for 2006 they're something like 50 per cent higher than they were a few months ago," he said.
"If you look at the forward market prices they're pretty high both for early next year and for the next winter as well."
He continued: "With wholesale prices where they are, all suppliers are going to have to put prices up in 2006, and I think that is inevitable."