Energy suppliers are overcharging customers by an average of £74 per household each year as they refuse to pass on falling wholesale costs.The total figure will be an incredible £1.66bn in 2009, according to independent consumer watchdog, Consumer Focus.It reckons we'll all pay about £13.80 too much for electricity, £361m in total, and £60.10 each for gas, or £1.3bn overall. Current gas prices should be 7.4% lower and electricity 3.1% cheaper."Consumers have feared for months that the big six suppliers might not have passed on the full cuts in wholesale energy prices, but the companies claimed to have acted fairly," says Philip Cullum, Deputy Chief Executive of Consumer Focus "Energy firms should take immediate action to put things right for their customers. A failure to act, and to ensure that people pay a fair price for energy, could have serious consequences for the sector."Consumer Focus is calling on the government to intervene if the energy companies, Centrica-owned British Gas, E.ON, EDF, npower, Scottish Power and Scottish & Southern, refuse to act on their own.But the claims have been rejected by the Energy Retail Association, which argues that other costs have increased, while Ofgem also dismissed the findings."We are entirely confident in our analysis of wholesale and retail energy prices," said the energy regulator. "Although Consumer Focus has borrowed some of our methodology for calculating wholesale costs they appear to have made assumptions that are simply wrong. And we are concerned that they are misleading consumers."