The Renewable Energy Association said: “That money is effectively raised for renewables and it isn’t right it should be used not for renewables.”

The government is expected to announce a package of measures next week under which power companies will agree to help impove the energy efficiency of poorer households but it is likley to face difficult questions over why it is not using some of its own energy windfall to help the fuel poor.

Ed Matthew, part of a powerful coalition of lobby groups which will publish a charter on fuel poverty on Monday, said the government’s windfall should be spent on speeding up work to improve insulation in the poorest homes “over and above” what is already planned.

“This is a question of life and death: 20,000 to 40,000 people die every year because of cold in this country, and energy efficiency is the only permanent solution,” said Matthew, head of UK climate for Friends of the Earth. “Huge investment is required and the money has to come partly from companies and it has to come directly from government itself if we’re going to get anywhere close to the kind of investment required to solve the problem.”