ScottishPower will increase its standard domestic gas and electricity prices from this week in the UK.

Prices for gas customers will increase by an average of 2% and electricity bills by an average of 8.9%, and this price increase will affect 2.5 million households.

According to the company, the price change will add approximately £1 to the weekly cost of energy for a dual fuel customer paying monthly by Direct Debit.

ScottishPower director of Energy Retail Raymond Jack said that this change in prices is as a result of sustained increases in the wholesale energy market, with the wholesale costs for an average dual fuel customer up 26% since 31 March 2010.

"The rising burden of non-energy costs faced by Britain’s energy suppliers, including the cost of meeting government environmental and social programs and the cost of distributing electricity on the national grid, has also placed further upward pressure on energy bills," Jack said.

ScottishPower also recently outlined an investment program in Britain over the next two years, in order to modernize infrastructure and help reduce carbon emissions.

Approximately £4bn will be spent on developing renewable energy projects, implementing smart grid technology and enhancing the electricity network, the company said.