UK motorists are being charged the highest diesel prices in Europe, according to new analysis.

The RAC, which carried out the research, said there is “no good reason” why British fuel retailers are not cutting pump prices.

It found the average price of a litre of diesel at UK forecourts is 155p.

That is 5p more than Ireland and Belgium, which have the continent’s joint second most expensive diesel at 150p per litre.

Even with the 5p per litre cut in fuel duty in spring 2022, the UK has Europe’s joint highest rate of duty on diesel with Italy at 52.95p per litre, but Italy’s average pump price is 7p per litre cheaper at 148p.

France’s duty rate is the equivalent of just 1p per litre lower than in the UK, but its average price for diesel is 9p per litre cheaper at 146p.

The analysis is based on figures from the European Commission and the UK’s Competition and Markets Authority.

Government figures show diesels make up around a third of all cars licensed for use in the UK – 11.4 million.

The vast majority of commercial vehicles such as vans and lorries are also powered by diesel.

RAC fuel spokesman Simon Williams described having Europe’s most expensive diesel as “a very dubious honour” for the UK.

He said: “The average retailer margin on diesel – that’s the difference between the delivered wholesale price and the retail price before VAT – is 18p.

“That’s a shocking 10p more than the long-term average.

“The average price of a litre of diesel should really be down to around the 145p level if retailers were charging fairer prices.

“The margin on petrol is also, in our view, unreasonably high at 13p.

“We can see no good reason why retailers in Britain aren’t cutting their prices at the pumps.

“It’s important to note that in Northern Ireland, where there is greater competition for fuel in the absence of supermarket dominance, the average price of diesel is just 144.9p – 10p less than the UK average, and petrol is 6p cheaper at 142.4p.”

The UK’s petrol is only the 11th most expensive in Europe at an average of 149p per litre.

Europe’s most expensive petrol is in Denmark, where drivers are typically charged 175p per litre.

Independent fuel retailers in the UK have said they are facing various cost increases, such as business rates, energy bills and wages.

Mr Williams added: “There is cause for hope for fairer fuel prices in the future as the Digital Markets, Competition and Consumers Act became law on Friday, giving new powers to the Competition and Markets Authority to closely monitor road fuel prices and report any sign of malpractice to the Government.”