Full guide
Fuel competition is mostly local
The national average is useful as a benchmark, but it is not the price any one forecourt has to charge. Retailers watch the stations that drivers realistically consider nearby. When several forecourts compete for the same journeys, a price rise is easier for drivers to avoid. Where there are fewer practical alternatives, that pressure is weaker.
The Competition and Markets Authority found that local concentration and the presence of a supermarket both affect prices. That is why the useful comparison is not simply your town against the UK. Start with fuel prices by location, then compare individual forecourts that fit the journey you are actually making.
The mix of forecourts changes the local benchmark
A location with two supermarket forecourts, several independents and a major-brand site has a different competitive shape from a town served by one small forecourt. Supermarkets have often led on lower prices, but that is a market pattern, not a guarantee that every supermarket is cheapest today.
Motorway services sit in another market again. Drivers already on the motorway may value convenience more than a detour, and service areas compete with a smaller set of realistic alternatives. Rural forecourts can also face lower volumes and higher delivery or operating costs. Those situations should not be blended into one simplistic rule about brands.
National cost changes do not reach every pump at once
Wholesale fuel, biofuel costs, duty, VAT and retail operating costs all sit behind the pump price. Retailers buy on different schedules and make pricing decisions at different times. When the wider market changes sharply, one area can therefore move before another.
This is also why a short national fall does not mean every local sign has already dropped. Look at the direction of the national trend, then check current local prices before travelling. The two views answer different questions.
How to read a local average properly
An average describes the qualifying prices available for one fuel and place. It does not mean every station has reported, and it should never be used to compare unlike fuels. Coverage matters: an average supported by ten current petrol prices tells a stronger local story than one supported by a single forecourt.
Use the cheapest current price for an immediate decision, the local average to judge whether it is genuinely competitive, and the price range to understand the cost of choosing badly. Then weigh the saving against the extra journey rather than assuming the lowest number is automatically the best trip.
Sources and further reading
Primary evidence for the important factual claims in this guide. External links open in a new tab.