Analysis of 47.4 million British MOT tests has produced a number that cuts against one of the most persistent assumptions in the used-car market: above 120,000 miles, 16 per cent of electric cars fail their annual roadworthiness test, against 23.5 per cent of petrol cars.
The work was done by New AutoMotive and commissioned by the British Vehicle Rental and Leasing Association, published on 22 September 2026. The headline finding is real and the dataset is enormous. What the number measures, though, is narrower than the coverage suggests — and the gap between those two things is the whole story.
The numbers
Britain’s MOT is an annual safety and roadworthiness inspection, compulsory for every car over three years old. That makes it one of the largest consistent datasets on vehicle condition anywhere in the world — every car, every year, same test.
| Lifetime mileage | Electric | Petrol |
|---|---|---|
| 20,000-40,000 mi (32,000-64,000 km) | 12.0% | 11.7% |
| 90,000-120,000 mi (145,000-193,000 km) | 16.5% | 22.1% |
| Above 120,000 mi (193,000 km) | 16.0% | 23.5% |
Note the first row. At low mileage the electric car is fractionally worse. The advantage is not present from new — it appears with distance, and the crossover sits at roughly 60,000 miles, about 97,000 km. New AutoMotive’s chief executive, Ben Nelmes, put it in terms of shape rather than absolutes: beyond that point the EV failure rate “flattens” while the petrol rate keeps climbing.
A second figure in the study is arguably more striking than the headline one. At fifteen years old, 5.4 per cent of electric cars had left the road permanently, against 11.9 per cent of petrol cars.
Where the difference comes from — and where it goes the other way
The component-level results are the least surprising part, because they follow directly from how the two drivetrains work.
Brakes. High-mileage EVs showed substantially fewer brake defects. Regenerative braking does most of the slowing, so pads and discs on an electric car can still be near-original at mileages where a petrol car is on its third set. There is a caveat the study also found: EVs over ten years old showed more brake problems than petrol equivalents — discs that are rarely used corrode, and lightly-worked calipers seize.
Suspension. Fewer defects on EVs, despite the extra weight.
Tyres. Here the result reverses sharply. Electric cars recorded tyre defects at roughly 1.8 times the rate of petrol cars. Mass plus instant torque is hard on rubber, and this is not a minor footnote — it is a real running cost and a safety-relevant one. An EV that sails through on brakes can still fail on tyres.
Four things this number does not mean
The study is solid. The interpretation being layered on top of it is where the care is needed.
- An MOT failure is not a reliability score. The test checks brakes, suspension, steering, tyres, lights, structure and emissions. It does not check whether the car starts, whether the infotainment works, whether the drive unit has been replaced under warranty, or how many times it has been recovered on a truck. A car can be thoroughly unreliable and pass every MOT of its life.
- Nothing here measures battery health. The MOT has no battery degradation test, and the researchers say so plainly. For a used EV buyer this is the single most important unknown — the one number that determines the car’s value and usability — and this dataset is silent on it.
- There is a structural asymmetry in the test itself. Petrol cars must pass an exhaust emissions check. Electric cars have no exhaust and cannot fail that section. Some portion of the gap is therefore not the electric car being in better condition — it is the electric car having fewer ways to fail. Neither the study nor its coverage quantifies how much, which is a gap worth noting.
- Who paid for it matters, even when the work is good. The BVRLA represents vehicle rental and leasing companies. Its members run large electric fleets and sell those cars into the used market when the leases end, where “high mileage” is exactly the objection they need to overcome. The association’s chief executive, Toby Poston, said mileage alone should not put buyers off. That is an accurate reading of the data. It is also precisely what the industry that commissioned it needs the public to believe.
There is one more inconvenient finding that the headlines mostly skipped: hybrids recorded lower failure rates than both petrol cars and pure EVs across several categories. If the story were simply “electric is more durable”, that result would not be there.
The selection problem
One thing worth thinking about, which no dataset of this kind can fully resolve. A petrol car at 120,000 miles is an ordinary object — there are millions of them, owned by everyone, maintained to every imaginable standard including none.
An electric car at 120,000 miles in 2026 is not an ordinary object. That population is small and skewed: disproportionately fleet and leasing cars, serviced on schedule by companies with maintenance contracts, plus early-adopter owners who tend to be unusually attentive. The study compares cars of the same age and mileage, which controls for a great deal — but it cannot control for the fact that the two groups were owned by different kinds of people in different ways.
That does not make the finding wrong. It means the effect measured is partly the technology and partly the ownership profile, and the study cannot separate them. Expect the gap to narrow as EVs age into third and fourth owners who service them the way most people service a ten-year-old car: when something breaks.
What a used-car buyer should take from it
The practical conclusion survives all the caveats: high mileage on an electric car is less alarming than the same number on a petrol car. The wear items that make an old combustion car expensive — the ones attached to an engine, a gearbox and an exhaust — mostly are not there, and the brakes have been doing a fraction of the work.
What replaces the old checklist is a shorter and harsher one. On a high-mileage used EV, budget for tyres, have the brakes inspected specifically for corrosion rather than wear if the car is old, and treat a third-party battery health report as non-negotiable. The MOT certificate tells you the car is roadworthy. It tells you nothing about the most expensive component in it.