The company said gas prices will go up by 8.5% and electricity prices by 9%.

The price hikes will lead to a £113 increase in the average annual dual-fuel bill to £1,424, the company said, and will affect about 2.2 million customers.

Scottish Power blamed the move on the wholesale cost of energy, the cost of delivering gas and electricity to customers’ homes and the cost of compulsory environmental and social schemes.

Neil Clitheroe, Scottish Power’s CEO of Energy Retail and Generation, said: “We understand that these are difficult times for many families, and we have done what we can to hold our prices for as long as possible. Recently we announced a range of measures to help our most vulnerable customers this winter.

“We will now write to every customer who will be impacted by the price increase, and we would encourage anyone who is concerned to contact us so we can discuss their options.”

Four of the ‘big 6′ energy companies have now announced price rises. SSE will increase bills by 8.2% bills from 15 November, British Gas said prices will go up by 9.2% on 23 November, and Npower announced the biggest rise of 10.4% which will take effect from 1 December.

Earlier this week, Scottish Power agreed to pay customers £8.5m following an Ofgem investigation into mis-selling.

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