According to the annual Post Office Motoring on the Continent report, UK drivers heading to France and Spain are likely to be financially hit hard due to unleaded pump prices going up 9p per litre year-on-year in Spain and 7p in France.

This rise is due to sterling’s fall in value against European currencies, rather than local pump price hikes.

The report revealed that the cost of unleaded petrol had fallen in over half of the 18 countries it surveyed, while diesel was cheaper in over 80% of the holiday motoring destinations.

However, once the sterling exchange rate was factored in, drivers face forking out up to £19 extra for every 1,000 miles of unleaded motoring, and up to £11 more to drive 1,000 miles in a diesel car.

The biggest burden will fall on motorists driving cars that use unleaded petrol because of price increases of up to 12p per litre in 13 of the 18 countries surveyed, once the sterling exchange rate was applied.

The greatest increase will be felt for those heading to Spain, as motorists face a 7.4% increase and will pay £13.32 more for each 1,000 miles of motoring.

The same number of motoring miles will also cost more than a year ago – £10.66 – in France. Furthermore, at a cost of £236.10 for 1,000 miles, holidaymakers driving through France will pay £38.96 (20%) more than in Spain because of the higher price per litre – £1.56 compared with £1.30.

Andrew Brown of Post Office Travel Money said: “The disparity between what motorists pay for diesel and for unleaded petrol in Europe is in marked contrast to the UK, where diesel has long been more expensive.

“This was just one of the anomalies we picked up in this year’s survey, another being a difference of up 48p a litre in fuel costs across the eurozone.

“It may not make sense for holidaymakers to plan big detours just a save a few pounds, but the higher price of motoring on the Continent this year means they should plan their routes carefully before setting out so they keep costs down.

“One of the ways in which holiday motorists can keep fuel costs to a minimum is to detour off the motorways to fill up at a supermarket. Just like in the UK, these can be the cheapest places to buy fuel, whereas motorists are likely to find the highest prices on the main roads.”

The cheapest fuel will be found in Andorra and Luxembourg.