Petrol forecourt owners have been accused of maintaining high fuel prices while the UK is distracted by the general election.
Despite a fall in wholesale costs since the end of April, fuel prices at the pumps remain significantly elevated said a new report from the RAC.
On average petrol in the UK costs 146.3p per litre, which is “5p higher than it should be”, the automotive services group added.
Similarly, diesel prices in Britain average 151.5p per litre, making it the most expensive in Europe.
In contrast, prices in Northern Ireland are lower, with petrol at 141.1p per litre and diesel at 141.9p per litre.
RAC's head of policy, Simon Williams, said: "Our data clearly shows that pump prices haven't fallen in line with the reduction in wholesale prices, so drivers across the UK - with the exception of those in Northern Ireland where fairer prices are charged - are once again losing several pounds every time they fill up.
"We believe there's no good reason for retailers in Great Britain not cutting their prices at the pumps far further. We can only think they're hoping no one will notice due to the distraction of the general election."
The RAC has called for the Competition and Markets Authority (CMA) to intervene and ensure retailers align their prices with wholesale costs.
According to the group’s latest research current margins are 14p per litre for petrol and 16p per litre for diesel, compared to the long-term average of 8p per litre for both fuels.