War in the Middle East is having an uneven impact on global economies but “all roads” lead to higher prices and slower economic growth, an influential economic body has warned.

The International Monetary Fund (IMF), which advises on policy and gives financial aid to member countries, said it was stepping up support, especially to the most vulnerable economies.

The war’s impact is “both global and highly uneven”, with some countries likely to face a renewed cost-of-living squeeze, IMF economists wrote in a blog post on Monday.

Large energy importers in Asia and Europe are bearing the brunt of higher fuel prices and input costs due to the effective closure of the Strait of Hormuz, which has caused shipments of oil and gas to grind to a halt.

Countries like the UK and Italy have been particularly exposed by their reliance on gas-fired power, while France and Spain were relatively protected by their greater use of nuclear and renewable energy sources, according to the IMF.

The organisation also warned of mounting concerns about food prices shooting up because of disruption to shipments of fertiliser from the Middle East.

“The interruption of crop-nutrient supplies from the Gulf comes just as planting season begins in the Northern Hemisphere, threatening yields and harvests through the year and pushing food prices higher,” it said.

The most vulnerable countries will “bear the heaviest burden”, with people in low-income countries spending a bigger proportion of their incomes on food.

“Although the war could shape the global economy in different ways, all roads lead to higher prices and slower growth,” the IMF warned.

The ultimate impact depends on how long the war lasts and how much damage it does to infrastructure and supply chains, but the world may “settle somewhere in between – tensions linger, energy stays costly, and inflation proves hard to tame”, it wrote.

The IMF said it was supporting member countries, of which it has around 190, with policy advice and, where needed and co-ordinated with the international community, financial assistance.

Olly Harrison, who farms in Tarbock, on Merseyside, said he bought his fertiliser for a good price last year and now believes – due to a wet and cold spring and limited growing days left, added with the costs of diesel for machinery – he may be better off not planting.

Diesel prices have reached their most expensive level since December 2022, new figures show, as the Iran oil crisis escalates.

The RAC said the average price of a litre of the fuel at UK forecourts on Monday was 181.2p.

That represents a 27% increase from 142.4p on February 28, the day the war in the Middle East began.

Average petrol prices have reached 152.0p per litre, a rise of 14% from 132.8p over the same period.

RAC head of policy Simon Williams said: “Compared to the start of the Iran conflict, it costs £10.55 more to fill up a typical family car that runs on petrol, and £21.35 more for a comparative diesel car.

“The financial strain on the eight in 10 motorists that tell us they depend on their cars continues to build, and at a particularly rapid rate for those who drive diesel vehicles.”

The 29.2p price difference between diesel and petrol is the largest since at least 2003.

UK oil refineries are more geared towards producing petrol than diesel, so the country’s supply of the latter is more reliant on imports.

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.

Latest DVLA figures show there were 16.2 million diesel vehicles licensed in the UK as of the end of September last year.

This included the vast majority of light goods vehicles, such as vans.

Steve Gooding, director of motoring research charity the RAC Foundation, described diesel as “the lifeblood of millions of small businesses” and warned that “white van man is bleeding cash just to stay on the road”.

He went on: “Whether you drive or not, soaring diesel prices will take money out of your pocket, either at the pump or in the bills you pay for everything from calling out the plumber to getting a home delivery.

“If oil prices remain at this level the impact on the forecourt could be felt for weeks, if not months.

“That’s bad news for everyone, not just drivers of the UK’s 4.6 million diesel vans, the majority of which will be used for work purposes.”

There are mounting calls for the Government to abandon the increase in fuel duty planned for September because of the rise in pump prices.

Chancellor Rachel Reeves announced in her November 2025 budget that the 5p-per-litre cut in fuel duty introduced by the Conservative government in March 2022 would only be extended until the end of August 2026, with rates then gradually returning to March 2022 levels over the next five years.

AA president Edmund King said: “Government can consider what they do with fuel duty in September but, frankly, that is five months away, and arguably industry needs help now.

“With higher pump prices, the Government has been gaining more in VAT, so there is some ‘free’ money in the system that could be used to help drivers out.”

Downing Street has insisted forecourts are “well-stocked nationally” amid reports of pumps running dry in some locations.

Asked whether the Government was planning for any shortages, the Prime Minister’s spokesman replied: “We’ll always plan for all eventualities.”

He added: “To be very clear, as the PM (Sir Keir Starmer) has said and as the Government have said, and indeed industry have said, fuel production and imports are continuing.

“The UK benefits from diverse and resilient supply.

“Petrol stations in the UK are well-stocked nationally and any suggestion otherwise is incorrect.”