Original analysis
Are cars getting more reliable?
For their age, yes. Hold the age of the fleet constant and the MOT fail rate fell 1.64 points between 2022 and 2025. A 10-year-old car failed 25.8% of the time then and 23% now. The headline rate looks flat only because the fleet aged 0.97 years over the same period and cancelled the gain out.
The two numbers that matter
Crude fail rate
22.54% → 22.57%
What the raw figures say. Essentially unchanged, and misleading on its own, because an ageing fleet is pushing it up at the same time as cars are getting better.
Same age, like for like
22.54% → 20.9%
The same fleet age structure applied to every year, so only the age-specific rates can move. Down 1.64 points.
Fail rate at each age, then and now
The 2025 line sits below 2022 at almost every age. The gap is widest in the late single digits, where most of the fleet sits.
Year by year
| Year | Tests | Mean age | Crude fail rate | Same-age rate | Electric |
|---|---|---|---|---|---|
| 2022 | 32,378,620 | 9.79 | 22.54% | 22.54% | 0.37% |
| 2023 | 32,756,890 | 10.13 | 22.83% | 22.23% | 0.73% |
| 2024 | 28,690,800 | 10.54 | 23.18% | 21.85% | 1.29% |
| 2025 | 30,808,029 | 10.76 | 22.57% | 20.9% | 2.11% |
How the like-for-like figure works
Fail rate climbs steeply with age, so any comparison across years is really a comparison of fleet age unless you control for it. We take the age structure of the 2022 fleet, apply each later year’s fail rate at every single year of age to that same structure, and read off the result. If cars had not changed, the number would sit still. It falls.
What we tested and ruled out
Electric cars. The obvious objection is that EVs pass more often and there are more of them. Their share went from 0.37% to 2.11%, which is too small to carry a 1.64-point move. Assume the extreme case where every electric car passes and petrol and diesel still improved 1.27 points.
A distorted starting year. Cars tested in 2022 had been through the pandemic, with deferred servicing and a testing exemption behind them, so 2022 could be an unfairly bad baseline. Drop it: from 2023 to 2025 the same-age rate still fell 1.33 points.
The 2024 dip in volume. 2024 carries about 10% fewer tests than its neighbours, which could mean an incomplete file. The four years fall in order whether 2024 is included or not, so it is not driving the result.
What we could not rule out
Survivorship. If more of the worst cars are scrapped before they reach 10 years old, the 10-year-olds still being tested are a better-selected group, and that would look identical to cars improving. Nothing in this data separates the two, and it is the explanation we would most like to test.
Testing behaviour. How strictly the standard is applied can shift over time. We have no measure of it.
So the measured finding is that cars of a given age fail less often than they used to. Calling that improved manufacturing is an inference, and a reasonable one, but it is not what the data proves on its own.
Source
All 124,634,339 class 4 first-attempt MOT tests recorded in Great Britain across 2022 to 2025, from DVSA’s anonymised MOT data published under the Open Government Licence, retrieved 21 Sep 2026. Retests and aborted tests are excluded. Age is the whole years between first use and the test date.
Questions
Are cars getting more reliable?
For their age, yes. Holding the age of the fleet constant, the MOT fail rate fell from 22.54% in 2022 to 20.9% in 2025, a drop of 1.64 percentage points. The rate improved at 16 of the 18 ages we could measure.
Why does the headline MOT fail rate look flat then?
Because two things cancelled out. The average car taking an MOT got 0.97 years older between 2022 and 2025, which pushes the fail rate up, while cars of any given age got better, which pushes it down. The crude rate moved +0.03 points and hid both.
Is this just electric cars passing more often?
No. Electric vehicles went from 0.37% to 2.11% of tests, too small a share to move the figure much. Even assuming every electric car passed, which they do not, petrol and diesel cars still improved by 1.27 points on the same measure.
What age of car improved the most?
Cars in their late single digits. A 9 or 10-year-old car failed about 2.8 points less often in 2025 than in 2022. Brand new cars barely changed, and very old cars improved by around a point.
Does this mean my car will pass?
It shifts the odds, nothing more. A 23% fail rate at 10 years old still means roughly one in four fails first time. Condition and maintenance decide an individual car, and the tester checks the car in front of them rather than the average.
Which brands hold up best is a separate question, answered in brand reliability age for age, and so is whether electric cars are more reliable. Or see how a single model has moved on its own pass rate page, where the same ageing adjustment is applied per model, or check one car’s MOT history.