The 51 plate — September 2001 to February 2002

What mileage is normal for this period

Recorded odometer readings at test in 2025, banded to 2,500 miles, from 76,872 readings. The box is the middle half of cars; the line inside it is the median; the whiskers reach the 10th and 90th percentiles.

Half of the cars from this period tested in 2025 had between 71,250 and 138,750 miles on them — a spread of about 67,500 miles between cars of the same age. Below roughly 70,000 puts a car in the lowest-mileage quarter for its age; above roughly 140,000 puts it in the highest quarter, though mileage alone is not a condition judgement — the test record does not show how a car was serviced. The median works out at about 4.1k miles a year since registration. These are 2,500-mile band midpoints, so treat each as give or take a thousand or so.

The same cars, three years running

Cars first registered in the 51 plate period, tested in 2023, 2024 and 2025. Because the cohort is fixed, this shows two things at once: how these cars are ageing, and how fast they are leaving the road.

The number tested fell 30.5% between 2023 and 2025. Nearly all of that is cars from this period leaving the road — scrapped, exported or on a SORN — though a small part is cars still on the road whose test date drifted past a year end. Pass rates rose 2.9 points over the same three years. The cars in poorest condition tend to leave the road first, which lifts the average of those left behind.

What they fail on

The failure mix for cars first registered in the 51 plate period alone, not the national average.

Share of this cohort's failure items, 2025 — the 8 biggest categories shown (96.1% of the items); smaller categories are not listed.

What the tester warns about

Advisories are what the tester flags as worth watching — not yet a failure, but on the way. They are the best guide to what cars from this period will need next.

Share of this cohort's advisory items, 2025 — the 8 biggest categories shown (96.7% of the items); smaller categories are not listed.

Dangerous defects

8.8% of cars from this period tested in 2025 were found to have at least one dangerous defect — 1.5 points above the 7.3% rate across all cars. A dangerous defect is DVSA's statutory category for a fault posing an immediate risk to road safety: driving the vehicle before it is repaired is an offence, whatever the MOT certificate says.

What they run on

The fuel mix of cars first registered in the 51 plate period, as recorded at test in 2025, and how each fuel's pass rate compares. Petrol accounts for 73.3% of them. The dashed reference line is the 60.6% average for the whole period, so a column above it is a fuel holding up better than the cars around it.

The most-tested makes from this period

The ten makes with the most first tests in 2025 among cars first registered in the 51 plate period, and how each one's pass rate compares with the 60.6% average for cars of this period. Measuring them against all cars of every age would only show that these cars are old; measuring them against their own contemporaries shows which ones passed most often.

By number of first tests in 2025 among cars of this period. Each links to that make's own MOT statistics, across every age.

What the letters either side mean

The two letters before the 51 say where the car was first registered — usually the supplying dealer's region. They do not say where the car is now, and they are not the postcode areas on our MOT statistics pages, which record where a car was tested. The three letters after the space mean nothing at all. The full table of both is on the number plate guide.