Where drivers pay least for fuel: the 3.2p supermarket gap
By Anthony Sharkey, Chief Operating Officer, New Reg Limited · 26 Aug 2026
Official price data today: supermarkets undercut branded forecourts by 3.2p a litre on unleaded, and the postcode you fill up in matters as much as the brand.
Supermarket forecourts are selling unleaded for 3.2p a litre less than branded forecourts on average today, official government price data shows. On a 55-litre tank that is a saving of £1.76 simply by choosing where you fill up, and the diesel gap is 3.4p a litre.
The national average for unleaded at branded forecourts has moved up by 4.0p a litre over the past week.
Motorway services remain the most expensive place to fill up: unleaded there averages 20.6p a litre more than at ordinary branded forecourts, £11.33 extra on a full tank. Where possible, fill up before you join the motorway.
The postcode divide remains real. Across postcode districts with at least five forecourts reporting, BT46 is the cheapest for unleaded at an average of £7.28 a gallon (160.1p a litre), while CA10 is the most expensive at £8.59/gal (188.9p). That 28.8p-a-litre spread is worth £15.84 on a 55-litre fill.
The cheapest supermarket unleaded recorded today: COSTCO WHOLESALE SHEFFIELD, Sheffield (S9 4WU) at £7.04/gal (154.9p); ASDA, Newtownards (BT23 4EU) at £7.08/gal (155.7p); ASDA, Bangor (BT20 4SD) at £7.08/gal (155.7p).
Prices are drawn from the official government fuel price feed, which most UK forecourts now update through the day. Use the live search on this site to compare every forecourt near you before you drive.
**Figures taken on 15 September 2026.** All figures are computed directly from official UK government fuel price data (Open Government Licence v3.0), as published by fuel.co.uk. This page is refreshed with the latest prices, so the figures above are those of the date shown, not of the date it first appeared. Pump prices change through the day and may differ by the time you read this. Averages describe groups of forecourts, not every site within a group. This is general information, not financial or consumer advice.