A group of motoring organisations, including members such as the RAC, has written to the European Union demanding an investigation into soaring petrol prices.
The Federation Nationale de l'Automobile (FIA), which represents 35 million drivers, has called for an inquiry into how benchmark prices are set on the Rotterdam spot market - the main trading centre for Europe.
It also claimed that the way prices are determined is "far from transparent".
Petrol prices in the UK hit record levels last month, driven by the increase in the wholesale price of oil.
However, petrol prices did not come down very quickly as crude prices dropped back again. A full tank for an average car in Europe currently costs over £10 more than it did a year earlier.
Werner Krauss, chairman of the FIA Eurocouncil said in the letter that "a platform with such a small volume is doubted to be a representative indicator for the vast European market".
Mr Krauss also wants the EU to look into the role of speculation on oil prices, adding that the FIA is very concerned about the "resulting volatility in fuel prices and negative financial impact on consumers".
The British Petrol Retailer's Association, which represents 6,000 petrol stations, also raised concerns about the issue of transparency. It is to insist the UK Office of Fair Trading to find out whether its members are being offered a fair deal.
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