Petrol prices in the Spalding area are at least 3p a litre higher than they should be, according to the AA.
National statistics show average petrol prices have gone down from 138.95p a litre in mid October to 135.08p now, with diesel dropping from 143.74p a litre to 141.89p.
According to PetrolPrices.com, the lowest price in Spalding before the weekend was 132.9p at Sainsburys in Station Road. The highest was at MRH Spalding in London Road at 134.9p.
Within a 10-mile radius, the cheapest was at Morrisons in Wardentree Lane in Pinchbeck and the highest at the Co-op Filling Station in High Road, Whaplode.
The fall in wholesale petrol prices across Europe should have knocked UK pump prices down by 10p per litre, the AA said.
Paul Watters, head of public affairs at the AA, has called on retailers to match wholesale prices. He said: “Petrol prices go up like a rocket and come down like a feather.
“We had access to wholesale price data which shows that from the beginning of October prices fell by at least 10p a litre. We’re only seeing a slow reduction in price (for motorists) to date - about four pence per litre.
“Drivers are not getting exactly a fair deal.”