Diesel drivers are facing 15p-per-mile charges in February. According to the latest RAC figures for diesel, the average price per litre is currently 140.97p for diesel at forecourts across the UK.
By the start of February, the price of diesel had dropped by 3p in the past month and 5.5p since the beginning of December, though it remains higher than it was back in 2021.
According to motoring and insurance website Nimblefins, the average fuel economy of UK diesel cars is 43mpg (though this can be lower for city-only driving), which means that, based on the current price per litre, it currently costs 15p per mile to run a diesel car, not including any other costs such as maintenance.
At the same time, petrol costs have dropped too, down to 131.9p for the average litre of unleaded, having fallen by 3p in January as well. Given the average fuel economy of petrol cars, it means the cost of running a petrol car is 16p per mile, so diesel remains the cheaper option once fuel economy is taken into account.
RAC head of policy Simon Williams said: “Seeing the price of petrol dip under 132p is a genuine boost for drivers, rewinding prices to those we last saw four and half years ago. And with even cheaper prices available depending on where drivers fill up, this is a positive start to the year for household budgets, especially so soon after Christmas.
“The Competition and Markets Authority’s 2025 annual road fuel monitoring report published in December said competition in the sector had not strengthened and retailer margins remained at historically high levels, and in some cases had increased. It also confirmed, contrary to what the fuel retailers trade association had been arguing, that increased operating costs were not the reason for average margins on petrol and diesel being higher.
“Our analysis of RAC Fuel Watch data also shows a similar picture of retailer margins. So, had retailers passed on more of the savings they’ve benefitted from when buying new fuel supply on the wholesale market, the January price reductions would probably have been bigger.”
In recent months, the government also announced a new pay-per-mile tax, specifically for electric cars.
Chancellor Rachel Reeves unveiled the policy to introduce a 3p-per-mile tax for EVs which is set to take effect from 2028.
When coupled with the average cost of charging an EV at home, this would bring the cost of running an electric car to between 5p and 11p per mile.
The scheme is set to be implemented in 2028 following a consultation, and would cost EV drivers an average of £250 per year.
Motoring groups expressed concerns that such a tax could put some people off from switching to electric cars.
The Treasury faces a reduction in revenue from fuel duty as more drivers move from petrol or diesel cars to EVs.
Successive governments have found the prospect of introducing per-mile charges for driving – sometimes referred to as road pricing – too politically toxic.
Ms Reeves’s EV scheme will involve users estimating how far they will drive over the following 12 months, and making an extra payment on top of vehicle excise duty (VED).
If they drive more they will need to top up this amount, while some of the money would carry over to the next year if someone clocks up fewer miles.
Journey examples at 3p per mile include £12 from London to Edinburgh, £5 between Cambridge and Bristol, and £2 between Liverpool and Leeds.
EVs’ exemption from road tax, officially called VED, was removed in April 2025.
A Government spokesperson said: “Fuel duty covers petrol and diesel, but there’s no equivalent for electric vehicles.
“We want a fairer system for all drivers whilst backing the transition to electric vehicles, which is why we have invested £4 billion in support, including grants to cut upfront costs by up to £3,750 per eligible vehicle.
“Just as it is right to seek a tax system that fairly funds roads, infrastructure and public services, we will look at further support measures to make owning electric vehicles more convenient and more affordable.”