The cost of gasoline is artificially inflated as increases in the wholesale price of diesel are “loaded onto gasoline,” according to an analysis by the automotive organization.
Average gasoline pump prices moved a fraction of 1p from the record high on Thursday, according to figures from Experian Catalyst.
The cost reached 142.16 pence per liter, the highest price being recorded at 142.48 pence in April 2012.
Average diesel prices on Thursday were 145.68 pence.
The AA said wholesale price increases since the summer should in fact have allowed diesel to set new records, with gasoline squeezing 2.5 pence from its record high.
AA fuel spokesperson Luke Bosdet said: “The AA recognizes that there is probably still some turmoil in the fuel trade after the panic purchase, and this may well have disrupted diesel contracts.
“He also understands that it’s basic business for a retailer to charge more profit on some items than on others.
“But for gasoline retailers to claim that the rise in gasoline prices, and possibly a new record high, is completely due to circumstances beyond their control just doesn’t ring true and needs to be challenged. “
The Petrol Retailers Association warned Wednesday that fuel price records are “almost certain to be eclipsed” before the end of next week.
He insisted that the “main reason” he would do so is “the rising and rising costs of crude oil,” which he said have risen by more than 50% since January.
It comes as figures suggest more than a third of UK drivers couldn’t afford fuel at at the height of the shortage crisis.
An Office for National Statistics (ONS) survey found that 37% of people were unable to purchase fuel in the past two weeks because it was not available – more than double the proportion ( 15%) who reported difficulties when asked the same question two weeks before.
Stock levels at gas stations have now fully recovered, according to the Ministry of Business, Energy and Industrial Strategy.