Diesel at 197p While Oil Falls: Why Pump Prices Aren't Following

Imagine reading that crude and wholesale costs are heading down, then pulling onto a forecourt to find diesel at the best part of £2 a litre. If that has been your experience lately, you're not imagining it, and you're not alone.

According to the Birmingham Mail's report, diesel is averaging about 197p per litre even though wholesale oil costs have been falling. Petrol is sitting at around 168p. The AA also said some forecourts, particularly in London and the south-east, are still charging unusually high prices.

That raises an awkward question for every diesel driver: if the cost of the raw material is dropping, why isn't the price at the pump?

What the story tells us

Three details in the report matter.

First, the gap between the fuels. At roughly 197p for diesel against 168p for petrol, diesel is about 29p a litre dearer. Over a typical 50-litre fill, that is roughly £14.50 more than the same volume of petrol would cost (about £98.50 against £84). For many years diesel was the cheaper option, which is why so many vans, taxis, company cars and family SUVs run on it. That calculation has flipped for a lot of people.

Second, wholesale costs are falling but pump prices are not following. This pattern is often summed up as "rockets and feathers": prices shoot up like a rocket when costs rise, but drift down like a feather when costs fall. Retailers will tell you that pump prices lag behind wholesale because they buy fuel in advance and are still selling stock bought at higher prices. Drivers tend to see it differently, and it is one reason regulators keep an eye on the sector. Our earlier piece on why petrol savings aren't reaching drivers covers that lag in more detail.

Third, the geography. The AA singled out London and the south-east, where some forecourts are charging what it called unusually high prices. Prices are set locally, and a station with few nearby rivals has more room to charge what it likes.

Why diesel is the harder hit

The source article gives us the headline figures but not a full explanation of the diesel premium, and I'd be wary of anyone claiming a single neat cause. Broadly, though, a few things shape the picture.

• Diesel and petrol are different products. They come from the same crude oil but are refined separately and traded in their own markets. Their prices can move apart.
• Tax works the same way on both, but bites harder on the dearer fuel. Fuel duty is a set amount per litre on petrol and diesel, and VAT is then added on top of the total. That means VAT takes a larger bite out of a higher pre-tax price, so any rise in the underlying cost is magnified at the pump.
• Demand is stubborn. Plenty of diesel buyers have little choice. A van driver, a tradesperson or a rural commuter cannot easily switch fuels, and retailers know it.

None of that makes 197p a litre feel any better, but it explains why the diesel price can stay high while the news about oil sounds positive.

Why it matters beyond your own tank

Diesel is not just a motorist's concern. It underpins deliveries, buses, haulage and farming. When it stays expensive, those costs tend to filter into the price of goods and services. If you drive for a living, a persistent diesel premium can eat into margins quickly.

There is also a fairness question. If wholesale costs are dropping and pump prices are not, drivers reasonably want to know where the difference is going. That is exactly the type of question the Competition and Markets Authority has looked at before. We looked at how that scrutiny has played out in our piece on the CMA probing UK petrol prices.

The legal angle: what is and isn't allowed

It is worth being clear about something many drivers find frustrating. A high price is not, in itself, illegal. There is no cap on what a forecourt can charge for fuel in the UK. Retailers are free to set their own prices, and they can differ from one street to the next. The rules that do apply are mainly about transparency and honesty.

This is general information, not legal advice, but here is how the framework broadly works.

Price display. Forecourts are expected to show their fuel prices clearly so you can see what you will pay before you buy. If the price on the pump or the sign is not what you are charged, that is a problem worth raising.

Unfair or misleading practices. Consumer protection law, including the Digital Markets, Competition and Consumers Act 2024, which replaced earlier rules on unfair trading, prohibits misleading actions and omissions. In plain terms, a forecourt shouldn't advertise one price and charge another, or present pricing in a way likely to trick you into paying more than you expected.

Competition law. If fuel retailers were found to be colluding on prices, that would be a matter for the CMA under competition law. Merely charging more than a rival is not collusion.

Price transparency schemes. The government has been developing a Fuel Finder scheme, designed to make forecourt prices easier to compare by requiring retailers to share price data. How well it is working in practice is a live question. We covered reports of petrol stations breaking Fuel Finder rules separately, and the details are worth checking against official government guidance as the scheme develops.

If you believe you have been misled about a price, the usual route is to raise it with the retailer first, then contact Trading Standards through the Citizens Advice consumer service. Keep your receipt and take a photo of the pump display and any price sign.

Practical advice for diesel drivers

You can't change the wholesale market, but you can avoid paying more than you need to. Here are some realistic steps.

1. Compare before you fill up

With a 29p gap between fuels and wide local variation, shopping around can matter. Use a price-comparison app or website to check forecourts near your route. If you're in London or the south-east, where the AA says some stations are charging unusually high prices, a short detour could pay off. Do the sums first, though: a 5p saving on a 50-litre fill is £2.50, which a long detour can easily wipe out.

2. Steer clear of motorway services unless you must

Motorway forecourts are typically among the most expensive because drivers have limited alternatives. If your tank allows, leave the motorway and fill up at a supermarket or independent station nearby.

3. Don't let the tank run low

Panic-filling at the first sight of an empty gauge is how people end up paying the highest local price. Planning a fill-up a little earlier gives you the freedom to choose.

4. Cut your consumption

When diesel costs this much, efficiency has a real cash value. Smooth acceleration, sensible speeds, correct tyre pressures and removing unnecessary weight all help. Our guide to the 60mph approach to cutting fuel costs looks at how much speed really matters.

5. Keep your receipts if you drive for work

If you claim business mileage or fuel costs, accurate records help. Check current HMRC guidance, as the rules differ depending on whether you are self-employed, an employee or running a company car.

6. Think twice about "cheap fuel" gambles

Don't be tempted to fill up and leave without paying, and don't use your phone behind the wheel to hunt for prices. Making off without payment is a criminal offence under the Theft Act 1978, and holding and using a phone while driving can bring a fixed penalty and points. Check prices before you set off, or when safely parked.

7. Know when a complaint is worth making

If the price charged does not match the price displayed, or you suspect you have been misled, raise it on the spot and follow up with Trading Standards via Citizens Advice. A merely high but accurately displayed price is not something you can challenge, so save your energy for genuine discrepancies.

Should you switch from diesel?

Many readers will be asking whether this is the moment to dump diesel altogether. I would urge caution before making a big financial decision based on a single price snapshot. The petrol-diesel gap can narrow or widen, and the right choice depends on your mileage, the type of driving you do and what you could get for your current car.

Diesel still tends to suit people who cover high mileage, tow or carry heavy loads. If you mostly do short urban trips, a diesel is often a poor fit regardless of price, which is also why diesels can struggle with particulate filters. Also bear in mind that older diesels may face charges in clean air zones, which is a separate cost to the fuel bill itself. If you are weighing up a change, look at the whole cost of ownership rather than the price per litre alone.

Looking ahead

The AA's message, as reported, is that falling wholesale oil costs should eventually feed through to the forecourt, though "dismal" is the word the headline uses for what diesel drivers face in the short term. I would treat any firm prediction with scepticism. Fuel prices depend on global events, exchange rates and refining capacity, none of which a motorist can control or reliably forecast.

What we can say is that the pressure on retailers to pass on savings is likely to continue. Regulators have shown interest in this area, government transparency schemes are being rolled out, and drivers have more tools than ever to compare prices. Whether pump prices fall in line with wholesale costs will be the real test.

Key takeaways

• Diesel is averaging about 197p a litre and petrol about 168p, according to the source report, so diesel is roughly 29p dearer.
• Wholesale falls do not always reach the pump quickly. The lag is common, though it frustrates drivers.
• High prices are legal. There is no cap, but forecourts must not mislead you about what you will pay.
• Location matters. The AA says London and the south-east have some unusually expensive forecourts, so compare before you fill.
• Avoid motorway services where you can, and plan fill-ups rather than topping up in a hurry.
• Raise genuine pricing discrepancies with the retailer, then Trading Standards via Citizens Advice.

For now, diesel drivers have to make the best of a frustrating market. A few minutes of price checking and some smarter driving habits will not bring the pump price down, but they can claw back a meaningful amount over a year of motoring.

This article is general information only and does not constitute legal or financial advice. For official guidance on consumer rights, contact Citizens Advice or your local Trading Standards service.