New reports suggest that one in three gas and electricity consumers are being over-charged due to their utility bills being based on an inaccurate estimate.

According to Consumer Focus, estimated bills are based on the latest charges, although they relate to energy which was used when the prices were at a lower rate. A third of all bills are based on this estimating scheme, meaning that 16 million people could be paying more than they should do.

You can check if your utility bills are based on estimated readings by checking your bill for the letter “E”, which means that the cost is estimated. Spokesperson for the group, Robert Hammond, said: “It’s in the interest of consumers to make sure bills are based on an actual meter reading.”

Representative for the power firms, The Energy Retail Association,  deny any profiteering from this and urge customers to send regular meter readings.