Ask any driver what frustrates them most about running a car, and the price of fuel will come up within seconds. One week the board outside the local garage looks almost reasonable; the next, the same tank of petrol costs noticeably more, and nobody warned you. For millions of households, fuel is one of the biggest regular bills after rent, food and energy — and one of the least predictable.
The truth is that the number on the forecourt sign is set by a chain of events that starts thousands of miles away, passes through currency markets and the tax system, and ends at a pump in your town. Understanding that chain does not make filling up cheaper, but it does explain why prices jump, why your neighbour in the next town pays less, and what you can actually do about it.
The oil price is only the start
Petrol and diesel are made from crude oil, and crude is traded around the world in US dollars. When the global oil price rises — because of wars, production cuts by exporting countries, or a surge in demand — the cost of the raw material behind every litre rises with it. When it falls, pump prices should eventually follow.
They rarely follow at the same speed, though. Prices at the pump tend to climb quickly when oil gets more expensive and drift down more slowly when it gets cheaper — a pattern drivers have complained about for years. Part of the explanation is timing: the fuel in a garage's tanks today was bought at yesterday's prices, and retailers argue they cannot cut prices until cheaper stock arrives. Motoring groups have long argued the falls still take too long, and the issue has drawn the attention of competition watchdogs more than once.
The pound in your pocket matters too
Because oil is priced in dollars, the strength of the pound quietly shapes what you pay. When the pound weakens against the dollar, the same barrel of oil costs more in British money, even if the global price has not moved at all. When the pound strengthens, there is room for prices to ease. It is one reason fuel can get more expensive in Britain at a moment when headlines elsewhere say oil is flat.
The tax slice is bigger than most people think
A large share of every litre you buy never reaches the oil company or the garage at all. Fuel duty is charged at a fixed rate per litre, and VAT is then applied on top of the whole price — duty included. In practice, tax makes up well over half of what many drivers pay at the pump, which is why changes announced in a Budget can move prices overnight, and why a freeze or cut in duty is always big news for motorists.
That also means the government benefits twice when prices rise: the duty stays the same, but the VAT take grows with the higher price. It is one of the reasons fuel taxation remains such a politically sensitive subject, and why drivers watch every Budget for one line about duty.
Why the next town is cheaper
If taxes and oil are national, why does fuel cost more on one side of a county than the other? The answer is competition — or the lack of it. In towns with several stations fighting for custom, prices are keener. In rural areas with one garage for miles, they are not. Supermarket forecourts have traditionally been among the cheapest places to fill up, using fuel to draw shoppers into the store, while motorway service stations sit at the other end of the scale, charging a premium to drivers who have little choice mid-journey.
The gap between the cheapest and most expensive forecourt in an area can be wide enough to matter over a year of driving. Fuel may also pass through an extra layer of distribution in remote areas, adding transport costs that city stations do not face.
What drivers can do
You cannot control the oil market, the exchange rate or the tax system. But there is still room to spend less:
- Shop around. Price-comparison apps and a glance at forecourt boards on your regular routes quickly reveal which local station is cheapest. A short detour for a full tank can be worth it; for a small top-up, probably not.
- Ease off the accelerator. Smooth driving — gentle acceleration, reading the road ahead, avoiding harsh braking — uses noticeably less fuel than aggressive driving, and it is kinder to the car.
- Check your tyre pressures. Under-inflated tyres increase fuel consumption and wear out faster. The correct pressures are listed in the handbook or on a sticker inside the door frame or fuel flap.
- Lighten the load. Roof boxes, bike racks and a boot full of clutter all add weight and drag. Take them off when you are not using them.
- Use loyalty schemes. Many supermarkets and fuel brands offer points or money-off schemes. The savings per fill are small, but regular drivers notice them over a year.
Thinking of changing cars?
Fuel prices feed into a bigger decision many drivers are now weighing: what to buy next. Diesel, once the default choice for high-mileage drivers, has lost ground as tax rules and clean-air concerns have shifted against it, though it still suits some long-distance drivers. Hybrids offer a middle path, cutting fuel use in town without any plugging in. Fully electric cars are far cheaper per mile on home charging, but cost more to buy, and public rapid charging can narrow that advantage considerably. The honest answer is that it depends on your mileage, your driving pattern and whether you can charge at home — there is no single right choice, which is precisely why the decision feels harder than it used to.
What happens next
Pump prices will keep moving with events far beyond any one driver's control, and forecasters warn against expecting a calm, steady period. The things to watch are the global oil price, the pound, and the government's decisions on duty at each Budget. In the meantime, the drivers who feel price rises least are usually the ones paying attention: knowing which local station is cheapest, keeping tyres right and driving smoothly. None of it is glamorous, but on a bill this size, small habits add up to real money.