ScottishPower said that in January 2008 the cost of coal, a key input, has risen by 97% and wholesale gas prices has risen by 83% compared to February 2007. From February 2008, the average customer will see a dual fuel increase of 14.8%.

Electricity prices will rise by an average of 14% across the UK and gas prices will rise by 15%. ScottishPower claimed that it will still be cheaper for combined gas and electricity services when compared to its competitor, British Gas.

ScottishPower has also announced the introduction of a new fixed price offer to shield customers from further increases until March 2011. Switching to the new fixed price deal, will reportedly protect customers from any further rises for more than three years.

Around one million of ScottishPower’s customers are already on capped or fixed price offers and will not be affected by the increase.

Willie MacDiarmid, ScottishPower’s director of energy retail, said: We have worked hard to protect our customers from these increases for as long as possible and offer consistently competitive energy prices. Like other energy providers, we are now forced to pass on some of these higher costs.