The top 10 in this list, model by model
1 · 59% fewer MOT fails
Audi A8
Why it ranks here: 59% fewer MOT fails than cars the same age and mileage (ratio 0.41, 95% CI 0.39–0.43), from 6,467 MOT tests at 11 to 15 years. At typical mileage its rate would be about 17.4% (16.5%–18.3%), against 42.1% for all cars at the same ages; raw (its own ages and mileage) 17.3%. Rank range 1–1.
Check before you buy: fails on number plates and VIN 1.3–1.8× as often as cars the same age (170 fails in 37,500 MOT tests at ages 3 to 15, not mileage-adjusted).
Suits: buyers looking at an executive car; the ones tested were mostly diesel.
2 · 51% fewer MOT fails
BMW 7 Series
Why it ranks here: 51% fewer MOT fails than cars the same age and mileage (ratio 0.49, 95% CI 0.47–0.52), from 6,925 MOT tests at 11 to 15 years. At typical mileage its rate would be about 20.8% (19.8%–21.7%), against 42.0% for all cars at the same ages; raw (its own ages and mileage) 20.7%. Rank range 2–4.
Check before you buy: fails on road wheels 3.9–4.5× as often as cars the same age (761 fails in 56,039 MOT tests at ages 3 to 15, not mileage-adjusted); fails on number plates and VIN 1.6–2.0× as often as cars the same age (277 fails in 56,039 MOT tests at ages 3 to 15, not mileage-adjusted).
Suits: buyers looking at an executive car; the ones tested were 71% diesel, 20% petrol.
3 · 50% fewer MOT fails
Audi A7
Why it ranks here: 50% fewer MOT fails than cars the same age and mileage (ratio 0.50, 95% CI 0.48–0.53), from 6,834 MOT tests at 10 to 13 years. At typical mileage its rate would be about 19.1% (18.2%–20.1%), against 38.1% for all cars at the same ages; raw (its own ages and mileage) 19.2%. Rank range 2–4.
Check before you buy: fails on number plates and VIN 2.0–2.4× as often as cars the same age (400 fails in 67,548 MOT tests at ages 3 to 15, not mileage-adjusted).
Suits: buyers looking at an executive car; the ones tested were mostly diesel.
4 · 49% fewer MOT fails
Porsche Cayenne
Why it ranks here: 49% fewer MOT fails than cars the same age and mileage (ratio 0.51, 95% CI 0.49–0.53), from 8,356 MOT tests at 10 to 15 years. At typical mileage its rate would be about 20.7% (19.9%–21.6%), against 40.5% for all cars at the same ages; raw (its own ages and mileage) 20.8%. Rank range 2–5.
Check before you buy: fails on number plates and VIN 2.2–2.6× as often as cars the same age (647 fails in 99,151 MOT tests at ages 3 to 15, not mileage-adjusted).
Suits: buyers looking at a large SUV; the ones tested were 44% petrol, 43% diesel.
5 · 45% fewer MOT fails
Mercedes-Benz S-Class
Why it ranks here: 45% fewer MOT fails than cars the same age and mileage (ratio 0.55, 95% CI 0.53–0.56), from 14,728 MOT tests at 6 to 15 years. At typical mileage its rate would be about 19.1% (18.5%–19.8%), against 35.0% for all cars at the same ages; raw (its own ages and mileage) 19.1%. Rank range 4–6.
Check before you buy: fails on road wheels 2.1–2.5× as often as cars the same age (639 fails in 84,211 MOT tests at ages 3 to 15, not mileage-adjusted); fails on number plates and VIN 1.5–1.9× as often as cars the same age (397 fails in 84,211 MOT tests at ages 3 to 15, not mileage-adjusted).
Suits: buyers looking at an executive car; the ones tested were 71% diesel, 24% petrol.
6 · 43% fewer MOT fails
Audi Q7
Why it ranks here: 43% fewer MOT fails than cars the same age and mileage (ratio 0.57, 95% CI 0.56–0.59), from 22,191 MOT tests at 8 to 15 years. At typical mileage its rate would be about 23.1% (22.5%–23.6%), against 40.4% for all cars at the same ages; raw (its own ages and mileage) 23.1%. Rank range 5–7.
Check before you buy: fails on number plates and VIN 2.1–2.3× as often as cars the same age (1,039 fails in 173,496 MOT tests at ages 3 to 15, not mileage-adjusted); fails on road wheels 1.2–1.4× as often as cars the same age (736 fails in 173,496 MOT tests at ages 3 to 15, not mileage-adjusted).
Suits: buyers looking at a large SUV; the ones tested were mostly diesel.
7 · 39% fewer MOT fails
BMW X6
Why it ranks here: 39% fewer MOT fails than cars the same age and mileage (ratio 0.61, 95% CI 0.58–0.64), from 4,600 MOT tests at 12 to 15 years. At typical mileage its rate would be about 25.9% (24.7%–27.2%), against 42.7% for all cars at the same ages; raw (its own ages and mileage) 26.0%. Rank range 6–11.
Check before you buy: fails on number plates and VIN 2.8–3.3× as often as cars the same age (515 fails in 60,064 MOT tests at ages 3 to 15, not mileage-adjusted); fails on road wheels 2.0–2.4× as often as cars the same age (448 fails in 60,064 MOT tests at ages 3 to 15, not mileage-adjusted).
Suits: buyers looking at a large SUV; the ones tested were mostly diesel.
8 · 39% fewer MOT fails
Lexus CT
Why it ranks here: 39% fewer MOT fails than cars the same age and mileage (ratio 0.61, 95% CI 0.59–0.63), from 16,287 MOT tests at 8 to 14 years. At typical mileage its rate would be about 22.7% (22.1%–23.4%), against 37.1% for all cars at the same ages; raw (its own ages and mileage) 22.7%. Rank range 7–10.
Check before you buy: no part fails significantly more often than on cars the same age (ages 3 to 15).
Suits: buyers looking at a family hatchback; the ones tested were mostly hybrid.
9 · 38% fewer MOT fails
BMW X5
Why it ranks here: 38% fewer MOT fails than cars the same age and mileage (ratio 0.62, 95% CI 0.61–0.63), from 41,720 MOT tests at 7 to 15 years. At typical mileage its rate would be about 24.7% (24.3%–25.1%), against 40.1% for all cars at the same ages; raw (its own ages and mileage) 24.7%. Rank range 7–10.
Check before you buy: fails on number plates and VIN 2.1–2.3× as often as cars the same age (1,744 fails in 283,682 MOT tests at ages 3 to 15, not mileage-adjusted); fails on road wheels 2.1–2.3× as often as cars the same age (2,033 fails in 283,682 MOT tests at ages 3 to 15, not mileage-adjusted).
Suits: buyers looking at a large SUV; the ones tested were mostly diesel.
10 · 36% fewer MOT fails
Jaguar XJ
Why it ranks here: 36% fewer MOT fails than cars the same age and mileage (ratio 0.64, 95% CI 0.61–0.67), from 4,874 MOT tests at 12 to 15 years. At typical mileage its rate would be about 27.6% (26.4%–28.9%), against 42.9% for all cars at the same ages; raw (its own ages and mileage) 27.6%. Rank range 7–16.
Check before you buy: fails on road wheels 1.9–2.3× as often as cars the same age (401 fails in 45,409 MOT tests at ages 3 to 15, not mileage-adjusted).
Suits: buyers looking at an executive car; the ones tested were 53% diesel, 47% petrol.
How we rank
8,699,109 MOT tests from 2022–2025 of cars 3 to 15 years old. For each model and age, the tests are split into 2 mileage bands (120-150k, 150k+); the expected fails are what all cars of that age would fail in the same bands, corrected to the model's own mix of test years. The ratio of the model's fails to the expected fails sets its place. The adjusted rate is that ratio times the all-car rate at the model's own ages, so it reads against that rate: a model tested only at 3 to 5 years is compared with young cars, not with this list's average.
The 95% intervals cover sampling error only (Wilson intervals). A model is called fewer or more only when its interval is at least 20% from the all-car rate, overall and at 3 or more ages ("close to average" when the interval excludes the all-car rate by less); awards use the same rule. Test years: Each model's expected fails therefore use its own mix of test years 2022–2025, age by age; the mileage bands themselves pool the four years, which can leave a small bias in favour of models first sold late in the window. Generations of a model are pooled unless the data splits them; each row says which years it covers. How we compare
Limitation: MOT tests record roadworthiness defects on the test day. They do not record breakdowns, engine or gearbox faults, or repair costs, and they cannot separate design from upkeep: a model whose owners service it before every MOT looks better here. Only cars still on the road are tested.