UK Fuel Price Index 2026: Petrol & Diesel Trends Explained

March 2026 Price Snapshot

12-Month Price Trend

UK petrol averaged 144.6p per litre in March 2025, making the year-on-year increase 8.3p (5.7%). However, this annual comparison masks a dramatic within-year move: petrol fell from 144.6p in March 2025 to 136.8p in October 2025 (helped by OPEC easing cuts and reduced global demand), then rose through winter to 138.9p by February 2026, before the Iran conflict drove a 14p spike in March 2026. The overall trend for 2025 was modestly deflationary for fuel prices; 2026 has so far been sharply inflationary due to geopolitics.

Diesel showed a similar but more pronounced pattern. From 168.1p in March 2025, it fell to 148.9p in October 2025 before rising to 153.7p by February 2026 and spiking 29p to 182.7p following the Iran conflict. The diesel-petrol spread has widened from 23.5p in March 2025 to 29.8p in March 2026.

Regional Price Variations

Region	Avg Petrol	vs National
London	156.2p	+3.3p
South East	154.8p	+1.9p
Scotland	155.6p	+2.7p
Northern Ireland	157.1p	+4.2p
North West	150.4p	-2.5p
Yorkshire & Humber	149.8p	-3.1p
East Midlands	150.1p	-2.8p

Price by Brand Category

The spread between brand categories has widened during the March 2026 price spike. The gap between the cheapest supermarket (Asda at 143.9p) and motorway services (173.4p average) is 29.5p per litre. Drivers who routinely fill at motorway services pay approximately £840/year more than those who systematically use supermarket forecourts. Branded stations (BP, Shell, Esso) average 157.2p — a 10.5p premium over supermarkets that amounts to £577/year extra for a driver doing 10,000 miles at 40 MPG.

Brent Crude Correlation

Analysis of 2020-2026 data shows that a 0 change in Brent crude translates to approximately 5.4-6.8p change in UK pump prices, with a typical lag of 12-21 days. The lag is asymmetric: rises transmit in 10-14 days, falls in 18-28 days on average. This rocket-and-feather pricing pattern has been a consistent feature of UK fuel retail and is monitored by the CMA under the 2023 fuel market review framework. During the March 2026 Iran conflict spike, the transmission lag shortened to approximately 10 days as the price movement was both large and sustained.

Seasonal Price Patterns

Excluding geopolitical shocks, UK petrol shows consistent seasonal patterns. Prices peak in July-August (summer driving demand), fall through September-October, and modestly recover through December-January. The typical peak-to-trough seasonal variation is 4-7p per litre. In 2026 this seasonal pattern has been overwhelmed by the Iran conflict geopolitical premium, but if conflict risk eases, autumn 2026 could see seasonal deflation compound any geopolitical relief to produce a meaningful price drop.

Q2 2026 Outlook

The central forecast for Q2 2026 is for petrol to average 146-160p per litre, with significant scenario uncertainty. Base case (55% probability): Iran conflict stalemate, Brent at 5-110, UK petrol at 148-158p. Bull case for drivers (25%): ceasefire or de-escalation, Brent at 0-85, UK petrol at 136-143p. Bear case (20%): escalation or Strait disruption, petrol above 165p. Subscribe to FuelFinderLive weekly price reports at fuelfinderlive.co.uk for updated data as conditions evolve.