Prices will rise for both electricity and gas consumers

Scottish Power's customers will pay 11.8 % more for gas and eight per cent more for electricity if they live in Scotland.

The increases are only slightly lower than those which will be introduced by British Gas next Monday and are similar to those announced by Npower last week.

The company blames the rises on an increase in wholesale energy prices.

The move will add �60 to the annual bill for an average customer receiving both gas and electricity, taking it from �569 to �629 a year.

The electricity price rise will be nine per cent for most of the UK, but eight per cent for customers in the central belt of Scotland, North West England and North Wales.

This is devastating news for ScottishPower's thousands of loyal customers in Scotland John Hanlon energywatch Scotland

Charles Berry, ScottishPower's executive director in the UK, said: "Like all electricity and gas suppliers, ScottishPower has been affected by the exceptional increase in wholesale prices.

"We have managed to absorb the rise longer than most but unfortunately are now forced to pass on part of this increase to our customers.

"However the good news is that customers can benefit from switching to our existing capped price offer which guarantees no rise in current prices for 15 months. More than 600,000 are already enjoying this benefit."

Pre-payment customers

ScottishPower announced last week that the price of electricity and gas for its existing 570,000 pre-payment service customers would remain unchanged over the winter until next March.

According to the company, wholesale energy costs have increased by 25% in the past six months.

ScottishPower, as well as British Gas and Npower, said these costs had left it with no option but to put up prices.

ScottishPower's gas prices are to rise by nearly 12%

John Hanlon, chairman of energywatch Scotland, the independent gas and electricity watchdog, condemned the rises.

"This is devastating news for ScottishPower's thousands of loyal customers in Scotland," he said. "It is clear that they continue to get a raw deal.

"The crumb of comfort ScottishPower offers by restricting the electricity price rises in Scotland to eight per cent compared to nine per cent elsewhere is at last some recognition that they have always been charging their local loyal customers too much for electricity compared with their customers in England and Wales."

He urged people to switch suppliers to avoid higher fuel bills.

The issue of gas pricing is also to be investigated by a group of MPs.