Bosses from the big six energy companies are being grilled by MPs this afternoon.
First on the agenda was why prices have gone up by an average nine per cent when wholesale costs of energy has increased by only 1.7 per cent.
A row has already erupted over the Ofgem data that claims the 1.7 per cent increase, as suppliers have blamed rising prices and government policies as the key elements pushing up consumers' bills.
E.ON's chief executive, Tony Cocker, said this afternoon that the firm has yet to decide whether or not to put up prices. EDF is expected to announce a winter increase soon.
Will Morris of SSE, which has unveiled an 8.2 per cent rise in dual-fuel bills, said that "people choosing to heat rather than eat" is "a massive concern for all of us".
In a bid to ameliorate concerns, Npower's Guy Johnson stressed that profit made is spent on investment. The company, which has around 3.5m customers, has seen the biggest price hike, with its average bill rising by 10.4 per cent on 1 December.
All six suppliers were quick to confirm that, in the event that green levies were rolled back, the savings would go to customers: Npower said yes, SSE, "unquestionably" so, and E.ON, "absolutely".
E.ON added that the green levies are a "regressive poll tax", a "stealth tax" .