Nine out of 10 people want an independent inquiry into the so-called "Big Six" energy companies, a survey has found.
More than 70% also want a levy on the providers' profits, according to the poll for pressure group Compass and environment charity Friends of the Earth.
Researchers for YouGov questioned 1,772 people, and 86% said they backed an independent public inquiry to look at EDF, E.on, British Gas, SSE, Scottish Power and Npower.
The survey found 71% supported a levy and 77% want money raised from a levy to be ring-fenced to help make homes more energy efficient and bring households out of fuel poverty.
It also revealed strong support for clean British energy, with 70% of people saying they want the Government to force the big providers to end the country's reliance on imported coal and gas by investing in power from the UK's wind, sun, waves and tides.
Andy Atkins, executive director of Friends of the Earth, said: "The Big Six energy firms are making massive profits from keeping us hooked on dirty coal and expensive imported gas.
"We all lost out from the Government's failure to stand up to the banks - now we need tough action into the ongoing scandal of cold homes, rip-off bills and the Big Six's influence over our politicians.
"The Chancellor must act immediately to ensure levies on energy bills are spent on making homes warmer and cheaper to heat, rather than disappearing into Treasury coffers."
Gavin Hayes, general secretary of Compass, said: "While many freeze, a few profit - this week we've heard of excessive energy profiteering at EDF, next week we'll hear of excessive profiteering at Centrica.
"This is why it's now time the Big Six paid a levy to redress this balance. Indeed our polling shows over two thirds of the public support a levy on excessive energy profits. The Government now has a simple choice - are they on the side of the Big Six energy giants or are they on the side of the people?"