Power bills 'to rise by more than £400 this year', say industry experts

The latest 15 per cent increase in bills could be followed by a second rise of 25 per cent before the winter, according to price comparison website uSwitch.com.

That would push annual bills up by a record 46 per cent during 2008, plunging 1.8million more Britons into fuel poverty.

Centrica, which owns British Gas, yesterday indicated that prices will have to rise again later this year to protect its profit margins.

The other members of the "big six" power suppliers - nPower, E.on, EDF, Scottish & Southern Energy and Scottish Power - are expected to follow suit. British Gas, which has 17million domestic customers, effectively sets the benchmark on prices for the entire UK industry.

Tim Wolfenden, of uSwitch.com, said: "If Centrica - the parent of British Gas, Britain's biggest supplier - is feeling such acute pressure over pricing then it's safe to say that others are feeling it too."

Research by uSwitch.com suggests the average annual bill will rise from £912 at the beginning of 2008 to £1,327 by January 2009 - up £415.

This means the figure will have doubled since 2005. The increases are putting a strain on millions of households, particularly pensioners and young families.

A 46 per cent rise in a year would suggest an extra 1.84million homes would be classed as fuel poor. This group face a nightmare choice between heating and eating.

Many price comparison websites are suggesting householders sign up to fixedrate contracts to protect themselves.

Centrica's operating profits for the first half of last year were £1.25billion, with £1.95billion for the full year.

The company insists it needs to make such a large profit to fund investment in clean energy.