Energy bills are being increased despite wholesale prices remaining almost flat, new figures show.
Data from industry regulator Ofgem has revealed that wholesale cost increases add just £10 to the average £600 household bill.
This 1.7% rise compares to the 9.1% average increase to gas and electricity bills announced by power giants in recent weeks.
Prime Minister David Cameron’s official spokesman called on the companies yesterday to explain the rises.
Senior executives from the “big six” suppliers are due to be grilled on pricing by MPs today.
On the eve of the committee hearing, the Scottish Federation of Housing Associations called on governments and companies to take action to stop the increases.
The group’s policy manager, David Stewart, said: “Currently, one third of Scotland’s households are living in fuel poverty and the recent price rises will only exacerbate this.
“Energy companies have in part used the cost of green measures to justify the significant hikes to household bills.
“The Department of Energy and Climate Change estimates that the cost of these obligations is 6% of the average domestic bill.
“This is a significant sum, but not enough to explain or justify double-digit price rises.” Labour said that the Ofgem figures showed the government was failing to get tough with companies amid mounting public concern at the soaring bills.
Shadow energy secretary Caroline Flint said: “Energy companies always blame rising global energy prices for putting up people’s bills, but these figures show that, under David Cameron, they’ve been increasing their profits on the back of spiralling energy bills for hard-pressed households.”
Energy Secretary Ed Davey is due to set out details this week of the competition test for the energy market to be carried out every year by Ofgem.
Mr Cameron announced the test last week.