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UK fuel prices: it's a postcode lottery, says RAC

  • Petrol and diesel prices rose in February
  • Biggest monthly increases since September
  • Huge regional differences in prices

Written by Graham King Published: 29 September 2023 Updated: 5 March 2024

Car running costs are on the rise once again as UK petrol and diesel prices jumped up in February. According to figures from RAC Fuel Watch, the average price of petrol across the UK is now 140.75p, while diesel costs 153.22p. That’s an increase of 4p and nearly 5p respectively since the start of February.

That means the cost to fill an average family car’s 55-litre fuel tank with petrol is now £77.41. The same amount of diesel costs £84.27.

The increase is being driven by a rise in the price of oil, which broke the $80 a barrel mark on 8 February. It’s been caused by the risk of attacks on ships – including oil tankers – in the Red Sea, forcing them to take a longer route around Africa. The British pound is weak against the US dollar, as well – not helpful when both oil and fuel are bought in dollars on the wholesale market.

Big regional price differences found

The RAC’s figures also showed that fuel continues to be much cheaper in Northern Ireland. Petrol is 5.6p per litre cheaper on average, while diesel costs 4.6p less. However, the RAC believes a more immediate concern is the massive regional price differences it found within Great Britain.

Looking at the fuel prices charged by the ‘big four’ Supermarkets – Asda, Morrisons, Sainbury’s and Tesco – the RAC found some huge variations.

Asda was the worst culprit, selling both the cheapest and most expensive petrol found at any supermarket – 136.7p and 154.9p respectively, the difference a whopping 18.2p. That means it costs as much as £10 more to fill a 55-litre tank at Asda depending on where in the country you are. Coincidentally, Asda is partly owned by petrol station operator EG Group.  

The regional difference in the price of diesel at Asda is also 18.2p. It has the most expensive diesel at 163.9p per litre, though Tesco beats it in offering the cheapest at 142.9p. Tesco’s fuel prices are the most consistent, with a variation of 7p for petrol and 11p for diesel across the UK.

What the RAC says

RAC fuel spokesman, Simon Williams, said: ‘Our data shows that in February, drivers endured the highest monthly fuel price increases since September 2023. What’s especially galling is the continuing difference in price between Northern Ireland and the rest of the UK.

‘It is also very clear there are some big differences between the cheapest and most expensive prices charged for both petrol and diesel [at supermarkets]. It’s important to remember this is the very same product being charged at vastly difference prices based just on location.

‘We hope that the eventual introduction of the monitoring body recommended by the Competition and Markets authority will help bring an end to this postcode lottery that treats drivers so unfairly.’

Fuel prices are due to a number of factors:

1. Crude oil price
2. E10
3. Delivery
4. Retailer margin
5. Fuel duty and VAT

Crude oil price

The price of crude oil is directly reflected in UK petrol and diesel prices. Indirectly, the cost of living is increasing as the price of goods and services have to be raised in line with the higher costs of running a business and its associated logistical operations – deliveries and so on.

The price of crude oil has has risen from a recent low of $75 a barrel to around $85, though that's still well below the 2022 high of $140. Prices continually fluctuate, however, as there are a number of ever-changing variables that contribute to its valuation.

After straightforward supply and demand calculations, the increasing number of unpredictable natural disasters, geopolitical instability, looming global recession and Russia’s invasion of Ukraine are all major factors in the price of oil. On top of that, Saudi Arabia recently announced it intends to cut oil production, which will also have a bearing on crude oil prices in the coming months.

The price of pump fuel is 90% determined by the wholesale price of Brent crude oil, according to RAC Fuel Watch. Whatever other factors may be in play, the price of crude oil is the dominant force behind the cost of fuel. Inconveniently, the price of pump fuel tends to lag behind that of crude oil, so it can be weeks before a fall in prices filters through to forecourts.

Delivery

The logistics of getting petrol and diesel to fuel stations via shipping channels and road tankers accounts for 1% of the total price of your fuel. That has a knock-on effect to business and industry, as well. Recent research by MoneySupermarket revealed that almost a quarter of vans drivers (24%) have turned down job opportunities because the high price of fuel means they are not cost effective.

It’s not clear if the on-going shortage of lorry drivers, which affects the fuel delivery sector of the haulage industry as much as any other, has had an effect on fuel prices. However, the shortages have driven up driver wages and we suspect a knock-on effect passed down to the consumer has been unavoidable.

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Test car editor Alan Taylor Jones stands in a Shell fuel station filling up a Mercedes SUV
Although prices have been falling, filling up is still a mightily expensive business.

Retailer margin

The mark-up charged by fuel retailers is the most contentious factor in the price of fuel. The RAC Fuel Watch team has been heavily scrutinising it for a long time; generally speaking, it can be anything from 2 to 10% of the price of a litre of fuel.

In June 2022, the Competition and Markets Authority (CMA) opened an investigation into forecourt prices, chief executive Andrea Coscelli saying it would, ‘provide advice to government on steps that might be taken to improve outcomes for consumers across the UK.’

In May 2023, the CMA reported that there is a significant lack of competition in the fuel retail industry, which is dominated by the supermarkets in Great Britain, and that has kept prices unduly inflated. For their part, petrol retailers maintain that their own costs remain high. The Petrol Retailers Association said that margins are, ‘often not enough to cover operating costs.’

Fuel duty and VAT

The tax we pay on the base price of fuel in the UK is a whopping 39% for diesel and 40% for petrol, which translates to a total of 52.95p per litre.

Fuel duty was cut by 5p per litre in the spring budget of 2022. While that move was welcomed, not all retailers passed it onto consumers – they’re not actually legally required to.

A public enquiry was called for in May 2022 by then-business secretary Kwasi Kwarteng but, in July the same year, the Competitions and Markets Authority found that, ‘on the whole, the fuel duty cut appears to have been implemented with the largest fuel retailers doing so immediately and others more gradually.’    

However, the CMA did say there was a need for a deeper study into the road fuel market.

Sarah Cardell, CMA General Counsel, said: 'On the whole the retail market does seem to be competitive, but there are some areas that warrant further investigation. These include finding out whether the disparities in price between urban and rural areas are justified.

'This area of work is a major priority for the CMA and if we can help, we will. That’s why we are immediately launching a market study that will use our formal legal powers to investigate this in more depth. If evidence emerges of collusion or similar wrongdoing, we won’t hesitate to take action.' No such action has been taken.

If one tax isn’t enough, Value Added Tax (VAT) is slapped on top of the price of fuel, inclusive of fuel duty, at a rate of 20%. Mercifully, rumoured plans for a giant 23% hike in fuel duty didn’t materialise in the 2023 spring budget.

E10 petrol

In September 2021, E10 petrol replaced E5 at UK fuel stations. Both are biofuels, ‘E’ refers to plant-based ethanol, 10 is the percentage of ethanol in the fuel mix. Doubling the renewably-sourced component in petrol is said to make it more environmentally friendly.

However, a number of Parkers’ readers have reported that they are seeing significant reductions in the fuel economy of their vehicles running on E10 petrol. Some have switched to more expensive Super Unleaded – still a 5% bio-mix – to maintain their vehicles’ fuel economy.

The ethanol mix accounts for 6% of the price of petrol; the wholesale cost of ethanol has recently risen, as well. Ethanol is also used in B7 diesel fuel, accounting for 9% of its price.

What you can do to reduce your fuel bills

Driving more economically will help the situation. Accelerating more slowly is an easy win, as is making fewer short journeys. Increasing the distance between your car and the one in front helps, as well – the extra space means you can brake more gently when it slows down.

These small changes to the way you drive have the same effect as compound interest. The difference in fuel economy may seem negligible at first but, over the longer term, it adds up to make a big difference.

You should also shop around for fuel. Remember that supermarkets aren't always the cheapest and consider using the Petrol Prices app, which shows the pricing in your area.

If you’re looking to change your car, look more closely at fuel consumption figures. While considering a switch to an electric car will give cheaper running costs in terms of Miles Per Pound, be mindful of increased domestic electricity usage to make an informed decision.

Is it worth switching to electric?

Many motorists are switching to electric cars to avoid all the hidden costs in fuel prices. It improves their green credentials, too. Alas, it doesn’t seem to be possible to avoid increasing costs.

The cost of domestic electricity has spiralled since the start of 2022, which could hit you hard when charging an electric car at home. Though costs are expected to drop later in 2023, it’s little more than a drop in the ocean at this point. Many roadside electric car chargepoint providers have also significantly increased their kilowatt-hour charges.

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