Higher tax tolls imposed by the Treasury account for almost 50% of last week's rise in household energy bills, power companies have claimed.

In response to the price hikes announced by npower, the Chancellor summoned the head of energy watchdog Ofgem, Alistair Buchanan, to a meeting at the Treasury to explain what can be done about rising bills.

One company told The Telegraph yesterday: 'Mr Darling can grandstand all he wants, but we will not let him forget that a sizeable chunk of price rises is due to higher "green" taxes and other costs introduced by the Treasury.'

It is estimated that rises in the three main green taxes this year, including the Carbon Emissions Reduction Target, will add £28.50 to annual household bills. npower's price rise will raise its average annual electricity bill by £64.

A source at another energy company said: 'No one is against green taxes. Most of us are in favour. But it's a bit rich for a chancellor to give the impression that we're all profiteering when the Treasury is putting up our prices.'

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