Police forces are investigating a scam involving heating oil fraud, where customers are duped into purchasing oil from websites that never arrives.
Heating oil varies in price, but is currently between 50 and 60 pence per litre, on average. Most domestic heating oil customers will order anything up to 1,000 litres at a time.
Customers who have been duped in the scam order oil from web sites that offer particularly competitive prices, but never receive the oil. When they check further into the web site to chase their order, the web site has no contact details for the company behind it.
Mark Askew, chief executive of the Federation of Petroleum Suppliers, told the BBC: "The evidence we're getting anecdotally indicates to us it's a growing problem, but it's impossible to actually get a handle on how big it is, because there doesn't seem to be a central body pulling the numbers together."
Stephen Harrison, chief executive of the National Fraud Authority, which includes Action Fraud, says his organisation should be the first call when people think they have been a victim of this kind of scam.
West Yorkshire Police are working on complaints and say they are investigating about 50 cases. But a spokesman says the investigations are at an early stage, and no one has been arrested.