British diesel reached 199.18p a litre at the end of September 2026, the highest pump price in the country's history. Auto Trader's figures for the four weeks that followed show used-car buyers reacting faster than almost any previous fuel-price move has produced.
The month in enquiry share
| Measure (cars up to five years old) | 28 Aug 2026 | 27 Sep 2026 |
|---|---|---|
| Used EV share of enquiries | 20.0% | 25.8% |
| Used diesel share of enquiries | 6.6% | 3.2% |
| Used EV share of advert views | 19.4% | 22.6% |
| Used diesel share of advert views | 5.1% | 4.5% |
Two things are worth separating. The enquiry swing is dramatic: electric up 5.8 points, diesel down 3.4, which more than halves diesel's share in four weeks. The advert-view swing is far milder — electric up 3.2 points, diesel down just 0.6. Browsing shifted a little. Actually contacting a dealer shifted a lot.
One scope note, because the figure has travelled badly. Several outlets reported 25.8% as used EVs taking one in four of all leads sent to dealers. It is a quarter of enquiries for cars up to five years old, a much younger and more electric slice than the used market as a whole.
Forecourt speed, with a caveat our own August figures supply
| Days to sell | August 2026 | Late September 2026 |
|---|---|---|
| Used diesel | — | 34 |
| Used electric, all ages | 25 | 28 |
| Used electric, three to five years old | 20 | 25 |
| Whole used market | 30 | 29 |
"That shift is increasingly visible on forecourts too," said Ian Plummer, Auto Trader's chief customer officer. "The average diesel is now taking 34 days to sell — nearly a week longer than an electric car."
That is true, and it is not the whole picture. Set the September figures beside the August data this site covered and electric cars slowed as well: three days across all ages, five days in the three-to-five-year band that was then the fastest-moving stock of any fuel type in Britain. The overall market sped up by a day over the same stretch. Diesel is losing ground relative to electric, by six days; electric is not accelerating in absolute terms.
What the pump actually costs now
Filling an average family car with diesel is close to £100, roughly £31 more than before the conflict in Iran lifted crude. What Car? put the annual fuel bill for a typical diesel at £1,509 over the UK average of 8,000 miles, £435 more than pre-war pricing, and at £3,772 over 20,000 miles, up £1,087.
One dealer is refusing diesel, not the trade
The most repeated line of the week deserves care. Car Dealer spoke to three EV specialists on 1 October. One of them, Richard Symons of R Symons, is turning diesel part-exchanges away: "We don't want them either, so I'm afraid we are simply saying we cannot accommodate their part-exchange request at this time." The other two described demand rather than refusal. Richard Norris of Drive Green said demand had "increased notably" since the war began; Estelle Miller of EV Experts said buyers are "very stressed about the price of diesel on the forecourt."
Three specialists are not the British motor trade, and one refusal is not a policy.
What it means for Tesla owners
The Model 3 led Britain's record September for new electric registrations with 9,929 cars, and the Model 3 and Model Y dominate the three-to-five-year used band these figures track. Britain bought a record 110,761 used electric cars in the second quarter; demand at that end is what holds Tesla residual values up.
The caveat is the cause. This is a fuel-price shock, not a change in the cost of running an electric car, and an enquiry is intent rather than a transaction. If diesel retreats, the enquiry share can retrace as quickly as it moved. Transport & Environment's finding that most of the EV-versus-petrol depreciation gap is not depreciation is the structural argument for used EV values. September in Britain is the cyclical one.