BIG SIX bosses have “no excuses” not to slash gas bills, campaigners and MPs said yesterday, as the energy barons’ costs dropped to a record low.

Energy markets yesterday showed wholesale gas trading at 37.55p per therm, marking a continued drop from around 70p in December and the lowest rate in nearly four years.

Yet the average household gas bill has rocketed from £676 in 2013 to an estimated £716 this year.

The trend means that energy retailers are now running staggering profit margins on gas of about 10 per cent, according to market regulator Ofgem, padding their pockets at double the rate they enjoyed at this time last year.

Consumer group uSwitch’s Ann Robinson said it was clear that energy companies should cut prices if they cared about their customers.

“Against this backdrop it’s not enough for companies to freeze prices,” she said.

 The firms have previously baulked at talk of reduced tariffs, arguing that they have to hoard their profits in case of a proposed three-year price freeze under a Labour government in 2015.

But Labour’s shadow energy secretary Caroline Flint dismissed the Big Six’s barracking as simply “up to their old tricks.”

She said: “When wholesale prices go up, consumers’ bills rise, but when wholesale costs come down, consumers never see the benefit.

“There is no excuse for energy companies failing to pass on these savings.”

A Labour government would also give regulators the power to force companies to cut their prices when wholesale costs fell, she added.

Left-wing commentators yesterday urged Labour’s leadership to go further and offer voters a full renationalisation.

The Campaign for Public Ownership’s Neil Clark told the Morning Star that the party had begun “edging away” from its neoliberal bent of the past decade. But asking regulators to micromanage price controls was “illogical” when a state-owned company could simply buy and sell without the need for profit.

The party’s “halfway” policy had already brought Labour under attack from free-market mavens in any case, he said — “why not go the extra mile and bring it into public ownership?

“Then we don’t have to worry about forcing companies to do things, or will-they-won’t-they situations.”