Estimates suggest that profits from each household will rise from £45 to £65 by Christmas, prompting claims that large energy companies are profiteering.
The projections come as Ed Miliband pledged to change the law to force the gas and electricity giants to pass on price cuts to their customers.
The Labour leader says the current system of regulating the industry is failing to deliver a fair deal. He accuses firms of “making us pay more than we should”.
