Our own MOT research
Which cars fail their MOT most around Cambridge?
Our own analysis of 235,480 MOT tests in the Cambridge postcode area put Honda best and Renault worst, once you allow for how old each make's cars are around here. The gap between them is about 48%. Allowing for age is the whole job: without it the table ranks fleets by how new they are, and the order comes out wrong.
The table, age-adjusted
The index is the number to read. 1.00 means exactly average for cars of that age in this area, so 0.85 is fifteen per cent better than expected and 1.15 is fifteen per cent worse. The raw failure rate and the average age of each make's local cars are shown beside it so you can see what the adjustment is doing.
Only makes with at least 2,000 local tests are included, which leaves 23. Everything else is too thin to say anything about.
| Make | Index (1.00 = average for its age) | Raw failure rate | Average age here | Tests |
|---|---|---|---|---|
| Honda | 0.82 | 18.6% | 12.8 years | 8,712 |
| Audi | 0.83 | 16.4% | 10.2 years | 13,252 |
| Land Rover | 0.85 | 17.4% | 11.2 years | 6,122 |
| Suzuki | 0.87 | 17.5% | 10.9 years | 2,228 |
| Skoda | 0.87 | 16.3% | 9.5 years | 7,267 |
| Mini | 0.88 | 17.8% | 10.8 years | 5,754 |
| BMW | 0.90 | 17.8% | 10.3 years | 12,630 |
| Jaguar | 0.90 | 17.9% | 10.8 years | 2,331 |
| Toyota | 0.91 | 18.6% | 11.1 years | 10,769 |
| Volkswagen | 0.96 | 19.9% | 11.1 years | 24,007 |
| Mazda | 0.96 | 19.6% | 10.9 years | 4,276 |
| Hyundai | 0.97 | 18.7% | 9.8 years | 5,550 |
| Kia | 1.01 | 17.7% | 8.6 years | 8,542 |
| Volvo | 1.01 | 19.3% | 10 years | 5,709 |
| Seat | 1.02 | 18.6% | 9.2 years | 4,512 |
| Ford | 1.07 | 22.1% | 11 years | 31,901 |
| Mercedes-Benz | 1.07 | 20.7% | 10.2 years | 12,407 |
| Fiat | 1.08 | 23% | 11.3 years | 4,942 |
| Peugeot | 1.12 | 22.7% | 10.7 years | 8,757 |
| Vauxhall | 1.13 | 24.1% | 11.4 years | 17,729 |
| Nissan | 1.15 | 23.8% | 10.9 years | 10,409 |
| Citroen | 1.19 | 25.5% | 11.4 years | 6,280 |
| Renault | 1.21 | 25.4% | 11.3 years | 7,695 |
Why the raw numbers would have been wrong
Honda is the clearest case. Its cars round here average 12.8 years old, against 8.6 years for Kia, the newest fleet in the table. On raw failure rate alone the younger fleet looks better, because newer cars fail less. Hold the age still and Honda is ahead.
That is not a technicality. A league table of raw MOT failure rates is mostly a league table of which badge sells more new cars in an area, which is a fact about dealerships rather than about the cars. Adjusting for age is what turns it back into something about the vehicles.
What it does not mean about your car
It is not a reliability ranking. An MOT tests brakes, tyres, lights, suspension, structure and emissions on one day. It says nothing about engines, gearboxes, electronics or whether a car will start on a cold morning, which is what most people mean by reliable.
A large part of what separates these makes is maintenance rather than manufacture. A car failing on a bulb, a wiper blade or a worn tyre is telling you about its owner. That is the part you control, and it is the reason two cars of the same make and age can sit on opposite sides of this table.
Which side yours is on is not something a table can tell you. It takes somebody looking at the car, and on the kind of work this data covers that is a job that can be done where the car already sits, without it going anywhere or you losing a day to it.
What this does not show
This is one year in one postcode area, not a census and not a national picture. A make with fewer tests behind it carries less weight even where it clears the threshold.
The adjustment is for age and nothing else. It does not allow for mileage, how the car is used, or where it is parked, all of which matter and none of which are in this data in a form that can be split by make.
Model matters more than make. A manufacturer sells small hatchbacks and large estates, and they do not wear alike. The data supports a make-level figure and not a model-level one at this sample size.
CB is not Cambridgeshire. The postcode area takes in Newmarket and Haverhill in Suffolk and Saffron Walden in Essex, and leaves out Peterborough, Huntingdon, March and Wisbech.
Where your car sits on that table matters a great deal less than how it has been looked after, which is the part you decide, and the place that gets decided is a full service rather than the badge on the bonnet.
Find out where your own car actually stands
Tell us the make, the age and roughly what it has done, and we will tell you what it needs and what it costs, before anything starts. We come to your home or work across Soham, Ely, Newmarket, Cambridge and Huntingdon.
Flat £20 call-out, no mileage charges. 5.0 from 9 reviews on Google.
Related: our full MOT research, does mileage or age matter more, VW, Audi, Skoda and Seat servicing, BMW servicing explained.