The company reported a profit of £390m today, compared with £313m in 2011.

npower’s parent company, RWE, also reported a 10% increase in its earnings before tax last year. 

The news follows a winter of price hikes from energy suppliers across the board, with npower clients facing a hike of 8.8% last November. This pushed the average bill up £108 from £1,244 to £1,352 a year.

npower blamed external factors, such as Government policy, for driving up costs.

Ann Robinson, director of consumer policy at uSwitch.com, said: “These profits will make customers wonder exactly why npower had to hit them with a hefty price hike this winter.

“It’s a valid question and npower customers deserve a valid answer, especially those who were forced to go cold this winter for fear of the cost of heating their home.

“Just as we are telling the Government that affordability has to be at the heart of energy policy, we would also remind the energy companies themselves that being strong and financially secure is just part of the picture – there has to be a balance between healthy profits and people being forced to go cold.

“Investing in the UK is hugely welcome, but so is taking every step possible to help keep its citizens warm. In light of today’s announcement we would urge npower to cut its prices again.”

British Gas also reported profits of £606m, a rise of 11% in the last year, despite also hiking up prices last year. They also blamed ‘external factors’ for having to increase prices.

Consumers are being advised to help themselves by taking steps to protect themselves from high cost of energy by using less energy, making homes more energy efficient and shopping around for competitive energy rates.

uSwitch.com says that there is currently almost £250 difference between the cheapest and most expensive tariffs on the market – households can easily achieve a valuable saving just by moving to dual fuel, paying by direct debit and signing up to a competitively priced deal.

However, a report published today highlights that while 59% of consumers are ‘angry’ about recent profit increases, 48% think it’s ‘too much hassle’ to switch provider.

George Charles of www.VoucherCodesPro.co.uk, said: “Consumers do need to remember that the energy companies aren’t the NHS. They’re part of a privatised industry that has obligations to its shareholders, so we shouldn’t begrudge them a profit margin.

“But whilst the energy giants are so quick to increase the bills whenever there’s a rise in wholesale prices, they’re decidedly sluggish when it comes to lowering them once prices fall again.

“That said, if customers aren’t prepared to shop around for the best deal as we all should, what’s their incentive to do so?”