UK diesel price 2026: why it rose and what it means for your fleet

April 2026: the five-week rise

At the start of 2026 UK diesel prices were steady. The government's weekly average sat between about 140p and 145p a litre through January and February. Fleet operators had got used to calmer prices after the spikes of 2022.

That ended on 28 February 2026, when the United States and Israel began strikes on Iran. Within five weeks the weekly average for diesel rose from 142.15p (week commencing 2 March) to 186.75p (week commencing 6 April), an increase of 44.6p a litre, or about 31%. The following week it reached 192.14p.

Source: Department for Energy Security and Net Zero, weekly road fuel prices. Figures are UK averages including duty and VAT. Prices at time of writing for each date shown; they are not current prices.

Why one waterway affects your fuel bill

The Strait of Hormuz is the narrow sea passage between Iran and the Arabian Peninsula. According to the US Energy Information Administration, oil flows through the strait averaged 20 million barrels a day in 2024, equal to about 20% of global petroleum liquids consumption. When conflict threatens that route, traders price in the risk straight away. Wholesale fuel prices move first and pump prices follow within days.

Why diesel rose faster than petrol

Diesel has risen much more than petrol. In the week of 23 February 2026 diesel cost 9.75p a litre more than petrol. By the week of 28 September the gap was 24.12p. The UK relies heavily on imported diesel, so it is more exposed when international diesel supply tightens. The RAC has also pointed to the risk of US diesel export restrictions pushing prices higher.

For a haulage business this matters more than any headline. Your trucks and vans run on diesel, so the gap between the two fuels is a cost that falls on you, not on the average motorist.

What is in a litre of diesel

Part of the pump price has nothing to do with the oil market. At the 197.58p average for the week of 28 September 2026, the split is:

VAT-registered businesses can normally reclaim the VAT on fuel bought for business use, so the price that matters to your accounts is 164.65p a litre excluding VAT.

Fuel duty: what happens next

Fuel duty has been 52.95p a litre since the 5p cut of March 2022. The original version of this article described the plan set out at Budget 2025, the Autumn Budget of November 2025: keep the cut until the end of August 2026, withdraw it in stages between September 2026 and March 2027, then raise duty with RPI inflation from April 2027.

That plan has changed. On 20 May 2026, in response to rising fuel prices, the government extended the 5p cut to 31 December 2026. It also gave HGVs a 12-month vehicle excise duty holiday, paying £1 at renewals from 1 July 2026, and cut red diesel duty until the end of the year. The HGV Road User Levy is still payable. According to the House of Commons Library, duty is due to rise by 3p a litre from 1 January 2027, and the government still plans to withdraw the full 5p cut by 1 March 2027.

The Autumn Budget is due on 28 October 2026 and may change these dates. We will update this article after it.

What the rise costs a fleet

The easiest way to size the impact is per 1,000 litres. Every 1p a litre on 1,000 litres a week is £10 a week, or £520 a year. Between the weeks of 2 March and 28 September 2026 diesel rose by 55.43p a litre, or 46.19p excluding VAT.

Use your own fuel card data for an exact figure. If your contracts do not include a fuel surcharge or price review clause, this table is the conversation to have with your customers.

When will prices come down?

Nobody knows. Pump prices depend mainly on what happens in the Middle East, which no fleet operator, government or regulator controls. The 2026 figures show how quickly prices can move in both directions: down by almost 28p between mid-April and mid-July, then up by 33p by the end of September. The structural exposure, a heavy reliance on imported diesel and a single shipping chokepoint for a fifth of the world's oil, is not going away.

The sensible response is to stop planning around the pump price and start managing the litres you use.

How to track prices yourself

Do not rely on headlines. The Department for Energy Security and Net Zero publishes average UK pump prices for petrol and diesel every week on GOV.UK, with the duty and VAT rates alongside, and the full series back to 2003 can be downloaded. It is an official, independent index, which makes it a sound reference for fuel surcharge clauses and for budgeting. Compare it with the prices on your own fuel card invoices each month. If you are consistently paying well above the national average, look at where your drivers fill up before you look at anything else. Motorway services and remote forecourts usually cost more.

What fleet operators should do now

• Measure fuel use by vehicle and by driver. You cannot manage what you do not measure. FORS v7.2 already requires fuel data by vehicle registration, including AdBlue and the diesel-to-AdBlue ratio.
• Introduce an idling policy and review idle time from telematics data with drivers.
• Check tyre pressures fleet-wide and make them part of the daily walkaround check.
• Coach drivers with their own data on acceleration, anticipation and speed.
• Review routes and empty running, especially on collection and multi-drop work.
• Review customer contracts for fuel surcharge or price review clauses linked to a published index such as the government's weekly prices.
• Check HGV VED renewals from 1 July 2026 are charged at £1, with the levy paid.

Our guide to cutting fleet fuel costs sets out ten actions in detail.

How J&JL helps

We work with fleet operators across the UK to reduce fuel spend through compliance-led fuel audits, driver coaching built on your own data, and practical fuel policies. Our fuel audit reviews tachograph and telematics data, maintenance records and fuel purchasing vehicle by vehicle, then gives you a prioritised action plan, a driver briefing pack and a fuel KPI dashboard.