Phil Bentley, the managing director of British Gas, said the gas and electricity prices will rise for years to come because of green taxes and cost of upgrading the National Grid.
Between £80 billion and £100 billion of investment is needed to upgrade the National Grid and other power networks in the UK over the next decade, meaning higher bills for millions of householders.
Meanwhile the cost of green energy tariffs and taxes could also add around £140 to the average household bill over the next eight years. While he did not put a figure on what the total rise will be, the increase could be several hundred pounds.
Mr Bentley said: “People will have to pay more per unit [over the next 10 years] and they are therefore going to have to be more diligent in saving energy.”