Millions of customers face an average rise of more than 100 pounds each on their fuel bills.
Today, SSE became the first of Britain's big six to put up prices this winter, announcing that household electricity and gas tariffs are to increase by an average of 8.2% from November 15.
The energy firm's decision that has reignited a row over whether the government should step in.
ITV News contacted all the other major energy suppliers to see whether they'll follow SSE. None of them will rule out price rises.
Our consumer editor Chris Choi has this report:
Opposition leader Ed Miliband has attacked Cameron for failing to freeze energy prices, tweeting:
David Cameron has labelled Labour's proposed policy of freezing energy prices a con.
Speaking at a PM Direct event in York, the Prime Minister said it was a con because Labour would have no control over world energy prices.