Labour shadow energy secretary Caroline Flint has seized on damning figures from industry regulator Ofgem showing a profiteering rampage by electricity and gas giants.

Wholesale prices paid by energy companies rose by just 1.7 per cent over the past year, but the greedy companies have already announced whopping rises in household bills averaging 9.1 per cent.

Ms 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.”

Ofgem figures revealed that wholesale costs paid by energy companies for their gas and electricity supplies accounted for £610 of an average annual dual household bill of around £1,300.

But this wholesale component is only £10 higher than a year before.

However, Ofgem also pointed out that the forward wholesale price of gas for use this winter is 8 per cent higher than last winter and the wholesale winter price for electricity is 13 per cent higher.

Energy companies challenged the Ofgem figures, arguing that they bought some supplies over two years in advance and also used various “hedging” strategies.

A spokesman for Prime Minister David Cameron said: “It is for the energy companies to explain the decisions they have taken around bills to their customers.”

Ms Flint pledged a Labour government to freeze energy bills for 20 months and “create a tough new watchdog” with power to force energy companies to cut prices when the cost of energy falls.

The Prime Minister’s refusal to act showed he was “out of touch,” she said.

Minister Greg Barker will meet energy companies this week in response to widespread complaints that they are hoarding millions of pounds paid up front by people who pay bills by direct debit.

Energy Secretary Ed Davey will also set out details of an “annual competition test” for the energy market announced last week by Mr Cameron.

In an attempt to pep up notoriously toothless Ofcom, the government is also bringing in the Office of Fair Trading and the Companies and Markets Authority.