More than one million pre-payment gas customers have been overcharged because their meters are faulty, the industry has admitted.
About 1.5m meters have not been working properly since they were installed, some as long ago as 2007.
The industry body Energy UK said customers may have been overcharged by as much as 25p for each top-up. Those worst affected may have been overcharged by as much as £110, but most will have lost far less.
Chief executive Angela Knight said: “Suppliers are working hard to roll out a solution for an issue which has affected some pre-payment gas meters. The meters were manufactured with a problem where they over-collected from customers.
“However, the companies know who is affected and will be getting in touch directly to put the meters right and refund any money owed.”
She added: “The suppliers and the wider industry are all very sorry this problem has occurred, but are already getting in contact with customers.”
However, James Padmore, head of energy, comparethemarket.com said: “It is clear that scepticism still reigns over the accuracy of energy bills. Most people still have misgivings over the way their meter readings are handled by their provider. This is in spite of [regulator] Ofgem’s efforts to enhance transparency. Trust in the energy sector and its practices appears to remain low.”
He added: “The introduction of smart meters, due to be installed in all UK households and small businesses by 2020, cannot come quickly enough. Indeed, there is a powerful case to be made for bringing this date forward, as the real time, accurate reading of meters – reflected in people’s bills – is something that we think the UK public would warmly embrace.”