Why do petrol prices vary so much between filling stations? On the same road I’ve seen a 5p-a-litre difference on what must be an identical product, while the same chains charge differently from town to town.
Weird, isn’t it? Of all the things we buy, the price of petrol is probably the most transparently disclosed before we enter the retailer’s premises, and yet this only serves to leave us wondering why how much we pay can come down to where we live, or even on which side of the road we are driving.
Earlier this week, in Horsham, Sussex, you could pay anything between 136.9p and 140.9p a litre, according to figures from the UK motoring group the AA, while about 10 miles away in Crawley, prices were between 128.9p and 131.9p. There are Sainsbury’s, Tesco and Shell garages in both places, and all were charging less in Crawley. Sainsbury’s, for example, was charging 8p less – a difference of £4.40 on a typical 55-litre tank.
Luke Bosdet, the AA’s spokesperson on fuel pricing, says there are two primary problems that its members complain about: “The pump-price postcode lottery between neighbouring towns and communities, and the difficulty in locating bargain-priced fuel.”
As you note, the product is the same, and retailers all buy the same raw product. According to the motorists’ group the RAC, the wholesale price currently makes up about 23% of the cost of a litre of petrol. It is influenced by two things: “the oil price and the exchange rate”, says Simon Williams, the head of policy at the RAC. Oil, petrol and diesel are traded in US dollars, so in the UK “we need the pound to be as strong as possible against the dollar to pay a good price at the pumps”.
‘The range of fuel prices shows that competition is working’ … M6, West Midlands. Photograph: Visionary Language/Getty Images/iStockphoto
The wholesale price is always changing and the fluctuations are passed on to consumers. This means the price you pay will, in part, depend on when the retailer bought the petrol, as well as the contract it has with its supplier. Counterintuitively, smaller retailers can be more competitive than the big chains, since they are more nimble, and able to buy when prices are temporarily lower.
The biggest retailers will probably pay less for delivery because they are buying more, says Williams, but this is a small part of the equation. On top of the cost of the product and delivery, there is VAT and fuel duty. In the UK, these currently account for 56% of the price, according to the RAC. Then there are the operators’ costs, plus their profit margin.
The UK’s competition watchdog, the Competition and Markets Authority (CMA), has been keeping an eye on petrol retailers and at the end of last year it published a report on the industry, which it plans to repeat annually. It found that in the first half of 2025, supermarkets’ fuel margins averaged 8.4% while the other petrol retailers’ margins averaged 9.8%.
The supermarkets are important in the petrol market – they own about a fifth of UK forecourts, but sell about 40% of our petrol and diesel. Steve Walker from the website Auto Express says supermarkets see petrol prices as a way to get people into their stores and can use fuel as a loss leader. “The fuel companies don’t have [that] luxury,” he says.
So there are lots of factors explaining why prices vary from retailer to retailer, but what’s odd about petrol is that prices are not being set on a national level.
Walker says many of the big brands, such as Shell and BP, are run as franchises, “like McDonald’s. But unlike McDonald’s they don’t set the prices. The franchisee will go into a battle with the garage up the road.”
Competitive … supermarket fuel margins averaged 8.4% in 2025. Photograph: Hollie Adams/Getty Images
Despite being owned centrally, other retailers are behaving in the same way. Sainsbury’s referred me to the Petrol Retailers Association trade body when I asked it about its pricing, as did the Motor Fuel Group, which runs about 1,200 forecourts under a range of different brands, including Morrisons.
However, the Sainsbury’s website does address the issue of different prices at different locations. “We want to ensure our petrol stations remain competitive within their local area, offering customers a fair price wherever they live,” it says. “We therefore adjust the price at each station using locally gathered pricing information.”
Price variation is not a bad thing, but the motoring groups say customers are losing out. Bosdet says localised price matching “on the face of it sounds fair, until the matched prices become artificially high when compared to nearby areas. Essentially, price matching gives local retailers permission to charge more than they could because there is another more expensive retailer nearby (whose circumstances may mean their fuel is always dearer) setting the level.”
Wholesale petrol prices have been falling since late November, but costs on the forecourt have not come down so quickly – motorists frequently allege “rocket and feather” pricing – prices shoot up when the cost of the raw product increases, but drop much more slowly when it is coming down.
The decision by some supermarkets to not compete as aggressively on petrol prices has been bad news for consumers. The CMA’s report found that in 2017, supermarket retailers’ margins averaged 4% – less than half the level in 2025, while non-supermarkets made 6.4%.
In future, it will monitor prices and be able to recommend action if competition weakens. It has pushed for a government-run price comparison tool so that drivers will be able to see exactly how much the filling stations in their local area are charging – that will go live this year.
Dan Turnbull, the senior director of markets at the CMA, says: “Drivers could see lower prices if competition between businesses was stronger. The main issue is that motorists can’t easily compare a wide range of prices in real time.
“That’s why the fuel-finder scheme matters – it will make it easier to shop around and encourage petrol stations to compete harder for business. This could help reduce the disparities between neighbouring petrol stations and towns that we currently see.”
The Petrol Retailers Association says members are pricing fuel “competitively and fairly”. It adds: “The range of fuel prices shows that competition is working and to help motorists find the best deals in their area, we encourage them to download the free PetrolPrices.com app.”
Other price comparison tools exist, and the price you will pay is there to see before you drive on to the forecourt. If the price is higher than down the road, the RAC’s Williams says: “People should be voting with their right foot and driving on.”