The big six energy firms are being urged by the Government to hold prices until the middle of 2015, it has been reported.

The call, made barring any big increase in wholesale fuel costs, is to try to avoid another round of price rises that could be blamed on Government green levies, industry sources have told the BBC.

Annual bills could be cut by around £50 by the move, it is claimed.

The Department of Energy & Climate Change described the claims as speculation, stating there would be no comment on the issue ahead of next week's Autumn Statement.

Labour has promised to freeze energy prices for 20 months if it is elected.

On the prospect of the energy companies being asked to hold bills until after the next election, shadow energy secretary Caroline Flint said: "But the truth is that only by legislating for a freeze can we guarantee that it will happen.

"David Cameron won't do that because he's not prepared to stand up to the big energy companies."

The reports come as Labour leader Ed Miliband is set to pledge to end the energy "rip-off" today as he details proposals for reforming markets.

He is to call for a tough new regulator, and an independent body to plan new infrastructure and ensure the lights stay on.

He will also promise action to boost competition among suppliers, and simplify bills for customers.

The shake-up - described by Mr Miliband as the biggest since privatisation in the 1980s - would be implemented during the 20 month price freeze planned if Labour wins the general election.

Launching the party's energy green paper at Manchester Town Hall, Mr Miliband will refer to the famous "Tell Sid" campaign advertising British Gas privatisation under Margaret Thatcher.

"In the past three years it has become clear to everyone but this government that the energy market is broken," he is expected to say.

"Prices are rising year on year without justification. And Britain is not getting the investment in energy we need to secure supplies for the future...

"We have a new message for Sid: We will freeze your bills for 20 months. "We will reset the market with real competition and proper regulation so that prices are affordable.

"We will secure the investment we need.

"This Green Paper on Energy sets out how the energy market is failing consumers and failing Britain. And it explains how a One Nation Labour Government will secure energy which is affordable and available.

"We will stop you being ripped off and, together, we will power Britain into the next century."

An independent Energy Security Board would be created modelled on the Office for Budget Responsibility, to help draw up and implement a timetable for building energy capacity.

A new regulator will have powers to order firms to pass on wholesale savings to customers, and intervene in the market to ensure consumers will get good value in the future.

Other commitments in the green paper include: :: preventing power generation companies doing exclusive deals with their retail arms.

:: ensuring all environmental and policy levies on bills are delivering "value for money".