UK Diesel Price May 2026: National Average and How It Compares
TL;DR: UK average diesel price was 145.7p/litre on 5 May 2026 (RAC Fuel Watch), down 1.5p over the prior month. Supermarket diesel averaged 141.5p; motorway service stations averaged 164.2p. Diesel sits at a 7.3p/litre premium over unleaded petrol, around the historical average. Fuel duty on diesel remains 52.95p/litre, frozen since March 2022.
UK Diesel Price by Retailer Type (May 2026)
| Retailer type | Average diesel (p/litre) | vs UK average | Source |
|---|---|---|---|
| Asda | 141.2p | -4.5p | RAC Fuel Watch |
| Tesco | 141.6p | -4.1p | RAC Fuel Watch |
| Sainsbury's | 141.7p | -4.0p | RAC Fuel Watch |
| Morrisons | 141.4p | -4.3p | RAC Fuel Watch |
| BP | 148.9p | +3.2p | RAC Fuel Watch |
| Shell | 148.5p | +2.8p | RAC Fuel Watch |
| Esso | 147.2p | +1.5p | RAC Fuel Watch |
| Motorway services | 164.2p | +18.5p | RAC Fuel Watch |
Prices verified via RAC Fuel Watch weekly retail data, 5 May 2026. Individual sites within each chain vary; figures are national averages weighted by transaction volume.
Why Diesel Prices Move Differently from Petrol
Diesel and unleaded petrol share the same fuel duty rate (52.95p/litre) and VAT treatment, so price differences arise primarily from wholesale costs and refining margins. Wholesale diesel pricing reflects distillate demand from heating oil, road freight, agriculture, and shipping, all of which increase northern hemisphere winter demand and are weaker in summer.
The May 2026 diesel premium of 7.3p over unleaded petrol is consistent with historical averages of 5-9p over 2018-2024. The premium widened to 30p in early 2022 following Russian export disruption (Russia historically supplied 10% of EU distillate) but has normalised as refining capacity adjusted and trade flows rerouted.
Regional Diesel Pricing in the UK
Regional variation in May 2026 diesel pricing follows similar patterns to petrol: Northern Ireland cheapest (140-142p average), East Midlands and Yorkshire next cheapest (143-144p), London and South East slightly above national average (146-148p), Highlands and Islands highest (149-152p). Motorway service stations everywhere price 15-20p above local non-motorway averages.
The Competition and Markets Authority (CMA) reported in its July 2024 fuel market study that supermarket retail margins on diesel averaged 8.4p/litre, up from 5-6p historically, suggesting reduced retail competition. The CMA's monitoring continues; a fuel finder service for consumer use is scheduled for 2026 implementation.
Fuel Duty and Tax Components on Diesel
For a diesel pump price of 145.7p, the approximate breakdown is: wholesale cost 53p; fuel duty 52.95p (frozen rate); VAT at 20% on (wholesale + duty + margins) approximately 24.3p; retailer and distributor margins 15-16p. The combined tax (fuel duty + VAT) totals approximately 77.25p, or 53% of the pump price.
HM Treasury fuel duty receipts for 2024-25 were £25.0 billion (HMRC fuel duty bulletin, 2025). The OBR projected fuel duty receipts of £25.6 billion for 2026-27 (Economic and Fiscal Outlook, March 2026), with the temporary 5p cut continuing.
FAQ: UK Diesel Price May 2026
What is the current UK average diesel price?
RAC Fuel Watch reported a UK average diesel price of 145.7p/litre for the week ending 5 May 2026. Supermarket diesel averaged 141.5p; motorway service stations averaged 164.2p. Northern Ireland averaged the cheapest regional pricing at 140-142p.
Will diesel prices rise or fall through summer 2026?
Forward markets price Brent crude in the $72-75/barrel range through Q3 2026. Absent geopolitical shock, this implies diesel pump prices may stabilise or decline marginally through June-August 2026. Summer demand for distillate is typically lower than winter, which could ease wholesale prices further.
Why is diesel cheaper at supermarkets than at branded forecourts?
Supermarkets use fuel as a customer footfall driver into stores and operate on lower retail margins (8-9p in 2024) compared to branded forecourts (12-15p). Supermarket sites are also typically larger volume per pump, allowing fixed costs to be spread across higher throughput.
Last reviewed: May 2026. Prices verified via RAC Fuel Watch 5 May 2026 weekly data; CMA fuel market study findings July 2024; HMRC fuel duty bulletin 2025; OBR Economic and Fiscal Outlook March 2026.
