Millions of Scottish Power customers are facing sharp rises in gas and electricity bills within weeks, the company revealed last night.
Gas bills are set to leap by an average of 17 per cent while the cost of Scottish Power's electricity is to rise by 10 per cent, a statement issued after the close of trading on the London Stock Exchange said.
The rises, blamed on soaring wholesale energy costs, are set to come into force from July 10.
The company insisted that it had been forced to pass on the increases to customers after seeing wholesale costs jump by 80 per cent.
Scottish Power warned customers of the prospect of future rises last month when it unveiled a 47 per cent leap in annual profits to £675 million.
The group said around one million of its 5.2 million customers would avoid the rises because they are on a capped price deal.
The company's director of energy retail Willie MacDiarmid, said: "We now need to pass on some of these increased wholesale costs."