E.On has become the fourth of the 'big six' energy companies to increase prices on both gas and electricity. From the 13th September gas tariffs will increase by 18%, while electricity bills will go up by 11%.
According to E.On these increase were due to the 30% rise in wholesale energy prices since the start of 2011. This current increase follows an increase in February 2011 which saw gas rise by 3% and electricity by 9% for E.On's five million customers.
According to price comparison site Uswitch, E.ON's energy bills have increased by 22% this year, Scottish Power's by 21%, British Gas by 25% and SSE's by 22%.
There are only 2 of the 'big six' , EDF and Npower, yet to increase their prices but it is felt that announcements from these two companies are imminent.
Consumer groups are demanding action to be taken by Ofgem, citing the fact that energy wholesale prices are around one third lower than their 2008 peak.