The Chancellor has urged energy companies to reconsider their price hikes, in an interview with ITV News.
Households across Britain could be plunged into a "long, cold winter" after two major energy suppliers increased their prices today.
British Gas has confirmed they are putting their energy prices up for this winter by an average of six percent.
The chief executive of one of the country's biggest energy firms, npower, has admitted to MPs that his firm has not paid corporation tax for three years.
It comes after the company's profits rose 34% to £413 million last year.
Paul Massara told the Energy and Climate Change select committee that the company invested more than £5 billion over the last five years in UK infrastructure.
This investment, combined with losses in their retail business between 2009-2010, meant they weren't eligible for corporation tax.
Mr Massara said: "This is in no way tax avoidance, and all of our business is taxable in the UK.
"We've not paid corporation tax because we've been investing hundreds of millions to keep the UK's lights on."
Energy supplier npower has reported a big jump in profits after its customers faced a cold end to 2012 along with a 9% increase in energy tariffs.
Profits were up 25% at £390 million, compared to £313 million in 2011. It lost 70,000 customers last year but said its remaining 3.9 million used more energy in last year's freezing temperatures.
British Gas and EDF have also recently unveiled bigger profits for 2012 amid prices hikes.
A 62-year-old pensioner has spoken of her surprise after receiving an electricity bill which, at £14,334.38, was 180 times her usual amount.
Pauline Danton from Kent said she spent five hours on the phone to fuel provider npower, who have since apologised and blamed the bill on a computer error.
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UKPower.co.uk - This website offers you the chance to subscribe to an energy price newsletter with the latest news and money saving ideas. You can call them on 0800 320 2000 or take their online energy price comparison survey.
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Chancellor George Osborne has told ITV News that energy companies npower and British Gas should reconsider their price hikes and "see if they are absolutely necessary at a time like this".
He said: "Of course I’m concerned when I see electricity bills going up and partly that is because of things beyond our control – what’s happening in the world with oil prices and gas prices.
"We’ve also got to do everything we can in Britain to try and keep those bills down. I would urge those energy companies to look again at any increases to see if they are absolutely necessary at a time like this.”
Customers on a British Gas tariff which sources power from renewable sources will see their electricity bills leap by 11%.
Around 4,000 customers on the sustainable energy tariff will see an increase which is almost double the rise in British Gas's dual fuel prices announced today.
The tariff matches every unit of electricity a customer uses with a unit of 100% British renewable energy.
This is very unwelcome, and I know lots of families who are struggling to balance their budgets will be very disappointed and concerned by these price rises. That’s why Government is taking action on a number of fronts: short-term measures to help people struggle with bills this winter, long-term measures to reform the market and bring in more competition.
What we need is action. We are bringing in the Energy Bill this winter that will reform the markets, it will be the biggest shake-up since privatisation, in addition, we are giving extra teeth to the regulator Ofgem.
– Energy and Climate Change Minister Greg Barker
We are also rolling out the Green Deal this winter. This is the biggest ever energy efficiency programme, that will help millions improve their homes so they are better insulated. This is probably the most ambitious energy efficiency programme in Europe, if not the world.
I am determined to help families, students in digs, pensioners, everyone, to benefit from the Green Deal, which will provide a long-term solution to people so they are less dependent on energy companies.
– Audrey Gallacher, Director of energy at Consumer Focus
Two price hikes on the same day will just reinforce the views and prejudices of consumers – whether justified or not - about a lack of transparency and competitiveness in the market.
People are not convinced that they are getting a fair deal. Unless they can be reassured about the relationship between costs, prices and profits, consumer distrust will continue, companies won’t get their message across, and the success of the regulator will be questioned.
Consumers need to see the Government and regulator taking big steps to help mitigate the rising cost of energy for customers.