The war that began on 28 February 2026 had one very visible effect on everyday life in Britain: it pushed petrol and diesel to their highest levels in more than two years. With the Strait of Hormuz — the narrow shipping lane that carries roughly a fifth of the world's oil and gas — effectively closed for over three months, wholesale costs surged, and the pump followed.
That picture changed over the weekend. On Sunday, the US announced a framework deal with Iran to end the war, including the reopening of the Strait of Hormuz and the removal of the US naval blockade of Iranian ports. Iran's national security council confirmed a memorandum of understanding, with a formal signing ceremony expected in Switzerland later this week. Oil markets reacted immediately, with crude tumbling to a three-month low.
Why oil matters at the pump: Crude is the single biggest ingredient in the price of petrol and diesel. As a rough rule of thumb, motoring groups reckon every $10 fall in the oil price feeds through to around 7p a litre off the pump price — though it takes a week or two to filter through to the forecourt, and retailers tend to pass falls on more slowly than rises.
Prices are already coming down
This isn't just a forecast — it's already showing up in the official figures. According to the government's weekly road fuel statistics, the average price of petrol in the week of 15 June was 155.54p a litre, down 2.41p on the week before. Diesel fell even harder, down 5.08p to 176.71p. That's the continuation of a slide that quietly began in late May, well before the deal, as the market started to anticipate an end to the conflict.
How prices have moved over the last month
| Week commencing | Petrol | Diesel |
|---|---|---|
| 25 May 2026 | 158.78p | 185.07p |
| 1 June 2026 | 158.74p | 184.11p |
| 8 June 2026 | 157.95p | 181.79p |
| 15 June 2026 | 155.54p | 176.71p |
Diesel had been the bigger casualty of the war, peaking at around 192p a litre in mid-April, so it has the most room to fall — and it's now leading the way down. The gap between diesel and petrol, which had ballooned past 30p at the height of the disruption, has narrowed to about 21p. Petrol, which topped out near 159p in late May, is easing more gently. We tracked that peak in our report on petrol prices hitting their highest since 2022.
Don't expect pre-war prices overnight
Here's the important caveat. President Trump has said prices will "drop like a rock" once the Strait reopens, but analysts are far more cautious. Restarting oil production that's been shut for months takes time; producers may hold back until they're confident the ceasefire holds, and the framework deal only opens a 60-day negotiation window rather than a final settlement. Several market analysts expect crude to hover near current levels through the summer, with a full return to pre-war prices unlikely until September or October — if it comes at all this year.
Worth remembering: A framework deal is not a signed peace deal. We've seen oil jump and slump several times this year on ceasefire hopes that later faltered — as we covered when the last ceasefire wobbled, and prices climbed straight back. If these talks break down, the recent falls could reverse just as quickly.
What this means for you
For now, the trend is genuinely in drivers' favour: the wholesale cost of fuel is falling, and that should keep feeding through to forecourts over the coming weeks. But two things are worth keeping in mind. First, retailers are usually quick to raise prices and slow to cut them, so the full benefit of cheaper oil tends to arrive with a lag — it pays to keep an eye on local prices rather than assume they've all dropped. Second, fuel duty is unchanged at 52.95p a litre, and VAT is still 20%, so a large chunk of what you pay isn't moving at all.
The practical takeaway: National averages are useful for seeing the direction of travel, but they don't fill your tank. When prices are falling unevenly, the gap between the cheapest and dearest station in the same town often widens — some forecourts cut quickly to win custom while others sit tight. That gap, frequently 10–20p a litre, is the saving you can actually control. We explain why prices differ across the same town.