Drivers are being urged to cut their speed by 10% as the Iran oil crisis continues to push up fuel prices. The AA said the simple adjustment can “improve fuel efficiency” while still allowing motorists to “keep up with the flow of traffic”.

It also advised drivers to avoid “continuous harsh braking” by anticipating traffic lights, roundabouts and changes in traffic flow. AA president Edmund King said: “It is well worth drivers adapting their driving style and speed both to save money and enhance safety. We estimate that diesel drivers can save £10 per tank by changing their driving style.”

Mr King also advised drivers to use fuel price comparison apps to find the cheapest petrol or diesel for their journeys.

“Often there are price discrepancies up to 19p per litre within short distances”, he warned.

The data is used by third-party fuel-price apps and websites.

Motoring services company the RAC said the average price of a litre of diesel at UK forecourts on Wednesday was 184.2p.

That is up 29% from 142.4p when the war began on February 28.

The average cost of petrol stands at 153.7p per litre, up 16% from 132.8p at the start of the war.

Oil prices – which have a significant effect on the cost of wholesale fuel – have soared in response to Iran’s stranglehold on tankers passing through the Strait of Hormuz.

Motoring research charity the RAC Foundation estimated that rises in pump prices have led motorists to pay an additional £583 million for petrol and diesel.

This consists of £439 million for diesel and £144 million for petrol.

The disparity is caused by a combination of the record price gap between the fuels and the greater volume of diesel sold.

The figures are based on average daily pump price rises and last year’s fuel consumption rate.