# Iran War Fuel Prices UK: How Diesel and Petrol Changed in One Month
B7 diesel in the United Kingdom rose from £1.477/L to £1.878/L between March 5 and April 4, 2026 – a 27.2% increase that makes Britain the hardest-hit country in Fuelconomy's five-nation European dataset. Based on our analysis of 4,404 UK stations tracked daily over 30 days, the national diesel average climbed on all 28 trading days without a single pause. No other country in our network recorded that kind of relentless upward pressure.
This analysis is based on Fuelconomy's historical price dataset covering 4,404 stations across the United Kingdom from March 5 to April 4, 2026. Daily averages, minimums, and maximums are calculated from official government price feeds (DESNZ). City-level data includes 78 cities with 20 or more reporting stations. Current prices shown at the end of this article update automatically.
The Iran conflict, which began on February 28, 2026, when the US and Israel launched strikes against Iran, has disrupted roughly 20% of global seaborne crude oil through the closure of the Strait of Hormuz. The knock-on effect at UK forecourts has been brutal – particularly for diesel drivers.
Over the 30-day period from March 5 to April 4:
(Based on Fuelconomy snapshot data, March 5 – April 4, 2026)
Diesel's 27.2% surge dwarfs the petrol increase by a factor of nearly two. The gap between diesel and petrol widened from roughly 11p/L before the crisis to over 31p/L by April 4 – the widest spread in Fuelconomy's UK data.
The trajectory above tells the story: B7 rose on every single one of the 28 measured trading days. That kind of unbroken climb didn't happen in any other country we track. France, Spain, and Italy all saw at least brief pauses or minor corrections during the same window.
The 27.2% diesel increase versus 14.5% for petrol isn't random. Diesel refining is more closely tied to middle-distillate supply from the Gulf, and the Strait of Hormuz closure choked the primary shipping route for these heavier products. European diesel supply was already tight heading into 2026 – the Competition and Markets Authority had flagged elevated diesel margins dating back to 2022. Layer a 10-million-barrel-per-day production cut on top, and diesel was always going to bear the brunt.
Across all five Fuelconomy markets, diesel outpaced petrol in percentage terms. But the UK stood out: the gap between its diesel and petrol increases was the widest anywhere in our network. Analysts point to the UK's status as a net importer of refined diesel – the country closed its last major refinery complex shift in Grangemouth, Scotland, and relies heavily on imports from the Middle East and India.
Not all UK cities felt the impact equally. Fuelconomy tracked 78 cities with 20 or more reporting stations. The differences are striking.
(Based on Fuelconomy snapshot data, March 5 – April 4, 2026)
Belfast's 35.7% diesel increase is the largest city-level jump Fuelconomy recorded across all five countries – not just the UK. The pattern is notable: cities that started with lower base prices (Belfast at £1.348, Cleethorpes at £1.421) saw the steepest percentage spikes as prices converged toward a national floor closer to £1.85/L.
(Based on Fuelconomy snapshot data, April 4, 2026)
Several of these cities – Bournemouth, Cambridge, Norwich – are brushing up against the £1.90 threshold. That's uncomfortably close to the all-time UK diesel record of 199.0p/L set in June 2022.
Drivers looking for relative relief found it in Belfast (£1.829/L), Harrogate (£1.852/L), and Huyton (£1.855/L). But "cheapest" is relative – even the most affordable city in the UK was paying 24% more than it was a month earlier.
A clear geographic pattern emerges from the data. While the absolute prices were highest in southern England (Bournemouth, Cambridge, Walton upon Thames), the biggest percentage increases hit Northern Ireland, Wales, and northern England.
Belfast (+35.7%), Pontypridd (+30.0%), Neath (+29.4%), and Llanelli (+28.9%) all sit outside the traditional pricing centre of the South East. The explanation likely comes down to competitive dynamics: these areas started from lower base prices, and when wholesale costs surged uniformly, they had further to climb to reach the new national floor.
For E10 petrol, the pattern held. Belfast again led with a 20.1% increase, followed by Llanelli (16.5%), Small Heath (16.2%), and Cleethorpes (16.1%).
With B7 at £1.878/L, the question of whether premium fuels make sense becomes sharper.
(Based on Fuelconomy snapshot data, April 4, 2026)
An interesting dynamic: premium fuels actually rose less in percentage terms than their standard counterparts. SDV climbed 16.9% versus 27.2% for B7, and E5 rose 11.3% against E10's 14.5%. The gap between standard and premium narrowed because premium was already priced at a level closer to the new equilibrium.
That said, SDV lost nearly a third of its reporting stations during the period – dropping from 2,119 to 1,362. That 36% decline suggests some retailers stopped carrying premium diesel entirely as supply tightened, prioritising standard grades.
For most drivers: Unless your vehicle specifically requires higher-cetane diesel or super unleaded, switching to the standard grade during a supply crunch saves money and is unlikely to cause any engine issues. Manufacturer octane/cetane requirements are in your owner's manual.
Here's what the 30-day diesel surge translates to in real spending:
For fleet operators, couriers, and haulage firms – who often fill 80 – 100L tanks multiple times per week – the exposure is far greater. The RAC Foundation estimated that UK drivers collectively paid an additional £307 million in fuel costs in just the first three weeks of the conflict.
What makes the UK's situation especially painful is the policy vacuum. Several European governments acted within days of the crisis:
The UK, by contrast, has maintained the existing 5p/L fuel duty cut introduced in 2022 but has not extended or increased it. The Chancellor's November 2025 budget actually scheduled the cut to begin phasing out from September 2026 – a plan that now looks politically untenable. Lord Richard Walker, Starmer's cost-of-living champion, publicly called for a larger cut, citing Australia's approach as a benchmark. Industry groups including the AA have pointed out that the Treasury is collecting more VAT revenue as prices rise – an effective "war windfall" on drivers' misery.
Key context: UK fuel duty stands at 52.95p/L. VAT at 20% is charged on top of the combined product price plus duty. At current diesel prices, the government receives roughly 95p of every £1.878 litre – over half the pump price.
The all-time UK diesel record stands at 199.0p/L, set on June 25, 2022, during the fallout from Russia's invasion of Ukraine. At £1.878/L (187.8p), the current national average is just 11.2p away from that peak. Several cities in the Fuelconomy dataset – Bournemouth, Cambridge, Crewe – are already within 10p of the record.
If crude remains above $100/barrel and the Strait of Hormuz stays effectively closed, Fuelconomy's data trajectory suggests diesel could breach the 2022 ceiling within one to two weeks. Petrol, at 156.2p, has more room before reaching its 2022 peak of 191.5p – but the gap is narrowing.
The price surge hasn't just squeezed wallets – it's raising questions about physical supply. Asda, one of the UK's largest supermarket fuel retailers, warned that it was facing fuel shortages at some stations. Shell's CEO cautioned that Europe could see broader shortages by April. Downing Street insisted forecourts are "well-stocked nationally," but acknowledged planning for "all eventualities."
The IEA estimated that roughly 20 million barrels of oil per day have been disrupted by reduced Strait of Hormuz shipping – equivalent to about 10% of global production. While the UK is less dependent on Middle Eastern crude than many Asian economies, its reliance on imported refined diesel leaves it exposed.
The snapshot above captures data through April 4. Prices continue to move. The live figures below reflect the most recent data from Fuelconomy's network of {[STATION_COUNT_united-kingdom]} UK stations. (Live data)
Use Fuelconomy's live price map to compare stations in your area. The spread between the cheapest and most expensive B7 station was £0.80/L on the final day of our snapshot – meaning the choice of where you fill up can save you £40 on a single 50L tank.
Based on Fuelconomy data from 4,404 UK stations, B7 diesel rose from £1.477/L to £1.878/L between March 5 and April 4, 2026 – an increase of 27.2%, or roughly 40p per litre. That adds approximately £20 to every 50L fill-up.
Not quite. The all-time UK diesel record was 199.0p/L in June 2022. The national average on April 4 was 187.8p/L – about 11p short of the record. However, some individual forecourts were already charging above 199p. Fuelconomy's snapshot shows a maximum station price of 200p/L.
Diesel refining relies more heavily on middle-distillate crude supply from the Gulf. The closure of the Strait of Hormuz disrupted a major shipping route for these products. European diesel supply was already tight before the crisis, and the UK's dependence on imported refined diesel amplified the effect. In Fuelconomy's data, diesel rose 27.2% versus 14.5% for petrol.
During the snapshot period ending April 4, Belfast had the lowest average diesel price at £1.829/L, followed by Harrogate at £1.852/L. However, prices are changing rapidly. Check the live widget above or use Fuelconomy to compare current prices across {[STATION_COUNT_united-kingdom]} UK stations. (Live data)
As of early April 2026, the UK has not introduced any new emergency fuel duty cuts or VAT reductions specifically in response to the Iran crisis. The existing 5p/L duty cut from 2022 remains in place but is scheduled to begin phasing out in September 2026. Several European governments – including Spain, Italy, Ireland, and Poland – have introduced temporary emergency reductions.
The UK recorded the highest percentage increase in both diesel (+27.2%) and petrol (+14.5%) among the five countries Fuelconomy tracks. France, Spain, Italy, and Portugal all saw lower percentage increases over the same 30-day period, partly because some introduced emergency tax relief that softened the blow at the pump.
If Brent crude remains above $100/barrel and the Strait of Hormuz remains disrupted, the upward trend is likely to continue. Fuelconomy's 30-day data showed no sign of prices stabilising – diesel rose on all 28 trading days without a single pause. Market analysts have warned that diesel could breach its 2022 record of 199p/L in the coming weeks.
The first month of the Iran crisis confirms what the data makes painfully clear: the United Kingdom is the worst-affected market in Fuelconomy's five-country European network. B7 diesel's 27.2% surge – with no single day of relief – outpaces every other country we track. The absence of emergency government intervention, while neighbours cut VAT and excise duties, means UK drivers are absorbing the full force of global wholesale increases.
The sharpest percentage increases hit Northern Ireland, Wales, and northern England – regions that could least afford them. And with the national average at 187.8p/L, the 2022 all-time diesel record of 199p/L is now a matter of weeks, not months, away.
Compare live prices across {[STATION_COUNT_united-kingdom]} stations on Fuelconomy and find the cheapest station near you before your next fill-up. (Live data)