Reading the curve: the youngest band is mostly cars at their first MOT, which is why it sits highest: nothing has had time to wear out. Pass rates fall fastest over a car's first 10 years, bottom out at 15 to 19, then rise again. That rise is about which cars are still around, not better engineering: a car still going for its MOT at 30 is usually well looked after. The line stops at 40 because most cars that old don't need an MOT.

Common isn't the same as dangerous. Tyres, wheels and suspension are the most common problem and the most dangerous: together with brakes, they make up 95.6% of all problems marked dangerous. Lights and electrics are nearly as common, but only 0.5% of them are marked dangerous.

What this tells you: BMW, Toyota and Land Rover come out on top whichever way you look: BMW is first overall and when their cars are 20 years old, and Toyota when their cars are 10 years old. Further down, age matters more: Volkswagen drops from 5th to 9th at 20 years old, while Vauxhall climbs from 9th to 6th. Four makes (Ford, Vauxhall, Peugeot and Renault) pass more MOTs at 20 than at 10, probably because the cars still going at 20 tend to be the better-kept ones. When the cars get to 20 years old, 9 of the 12 makes pass roughly 2 in 3 of their MOTs, so for an older car, how it's been looked after is likely to matter more than the badge. Worth remembering: this only covers passing the MOT. It doesn't tell you what a car costs to keep on the road, or about overall reliability.

This is the mix, not the amount. A bigger share of brake problems doesn't mean a Kia has more brake problems than other cars, just that brakes make up more of what's found. We checked each pattern across cars of different ages, just to be sure.

Why this matters: a flat national average of 7,100 miles a year treats every car the same. The real figures climb steeply through a car's first 15 years, peak at about 18 years old (around 102,700 miles), then fall to 55,300 by 39. Cars don't lose miles: these are different cars at each age, and high-mileage cars tend to be scrapped first, so the older cars still going for MOTs are mostly low-mileage ones.

Nearly one car in twenty on UK roads today (4.8%) would be charged in every zone that charges cars, such as London's ULEZ, purely because of its age, whatever it runs on. Scotland's Low Emission Zones work differently: a car that doesn't meet the standard gets a fine rather than a charge to enter.

What does g/km mean? The grams of CO2 a car gives out for every kilometre it drives. Lower is cleaner.

Why the jump? In September 2018 the official lab test changed to a longer, faster drive that's much closer to real roads. The same cars that scored 137 g/km on the old test scored 165 g/km on the new one.

What it means for you: official figures for older and newer cars aren't a like-for-like comparison. A newer car can look dirtier on paper when it isn't, but overall cars are getting cleaner as time goes on.

Most of the highest shares are models from the 1980s and 1990s that are no longer sold new. The few still around are more likely to be stored or used now and then than driven every day.

Deliveries kept going when commuting stopped. That's why vans only fell 9.2% in 2020 and lorries 5.8%, and why both were back above 2019 by 2021.

Cars were a different story: still 7.2% down in 2022, and 0.2% down in 2025.

Our vehicle lookup uses these same figures, so a car's typical mileage line allows for these quieter years instead of assuming normal driving all the way through.