Petrol retailers are under growing pressure to drop prices in line with the falling cost of oil.
The cost of a barrel of crude oil is hovering around $100, down from almost $150 at its peak in mid summer, but consumer groups say this has not been reflected in forecourt prices.
When oil prices were last below $100 a barrel in April, a litre of petrol cost on average 108.1p with diesel at 117.4p, according to the AAs monthly fuel price report.
The latest figures show that the average price is 112.8p for a litre of petrol and 124.3p for a litre of diesel. This has led to accusations that consumers are not being given a fair deal.
AA president Edmund King said: 'Allowing for the weaker pound and other factors, UK motorists are being overcharged.'