Our own MOT research
Where does the Cambridge area rank for MOT failures?
Mid-table, and that is the honest answer. Across 116 UK postcode areas and 29,603,003 MOT tests, the Cambridge area failed 28.4% of the cars it tested, which puts it 65th of 116, where first means fewest failures. Allow for how old the cars are here and it moves to 56th, which is as close to average as it is possible to land. The interesting number is not ours.
The gap between the best and worst areas is enormous
IG failed 20.1% of its cars. KY failed 36.3%. That is a spread of 16.2 percentage points, which means a car in the worst area is getting on for twice as likely to fail as one in the best. Both numbers come from the same test, applied to the same standard, by testers working to the same manual.
The average across all 116 areas is 27.8%. Cambridge sits a little above it, on a fleet averaging 11.1 years against a national 10.6.
| Rank | Postcode area | Failure rate | Average car age |
|---|---|---|---|
| 1 | IG | 20.1% | 9.9 years |
| 2 | RM | 20.7% | 10.2 years |
| 3 | UB | 20.9% | 10.7 years |
| 4 | BR | 21% | 9.5 years |
| 5 | SM | 21% | 11.2 years |
| 6 | NW | 21.4% | 9.6 years |
| 7 | HA | 21.5% | 10.5 years |
| 8 | KT | 21.5% | 10.5 years |
| 9 | SL | 21.5% | 10.9 years |
| 10 | TW | 21.6% | 10.4 years |
| … | … | … | … |
| 65 | CB (Cambridge) | 28.4% | 11.1 years |
| … | … | … | … |
| 107 | BA | 33.4% | 11.6 years |
| 108 | SP | 33.9% | 11.5 years |
| 109 | BS | 34.1% | 11.1 years |
| 110 | LD | 34.4% | 11.5 years |
| 111 | TQ | 34.6% | 12.4 years |
| 112 | TR | 35% | 12 years |
| 113 | DD | 35% | 9.4 years |
| 114 | EX | 35.4% | 11.9 years |
| 115 | PL | 35.4% | 11.8 years |
| 116 | KY | 36.3% | 9.7 years |
How much of it is just older cars
Some, and not all. Across the 116 areas, every extra year of average fleet age goes with about 1.32 percentage points more failures. That is a real relationship and it explains a good part of why the areas at the bottom of the table are where they are.
It does not explain all of it, and the leftover is where the interesting question sits. We can measure the gap. We cannot tell you from this data what else is in it: how far people drive, what the roads do to a car, how much is spent on maintenance, or how strictly a particular area tests.
What it means for your own car
A postcode average tells you almost nothing about an individual car. The spread inside any one of these areas is far wider than the spread between them, because it is driven by age, mileage and upkeep rather than geography.
The useful thing to take from a table like this is the size of the thing that is not geography. If where you live moves the odds by a few points and how the car has been looked after moves them by tens of points, then the second one is where the attention belongs.
Which is the better news, because it is the half you can do something about. Finding out where your own car stands takes somebody going over it properly, and on this kind of work that happens where the car already is, rather than the car having to go anywhere and you waiting on a slot.
What this does not show
This is one year of tests. It is directional, and an area with fewer tests behind it carries less weight, which is why areas under the threshold are excluded entirely.
The age allowance is a straight line through 116 points, failure rate against average fleet age. It is a direction, not a model, and it should not be read as isolating a cause.
A postcode area is not a county or a council. These are Royal Mail delivery areas drawn for sorting post, and they cut across local authority boundaries freely.
CB is not Cambridgeshire. It takes in Newmarket and Haverhill in Suffolk and Saffron Walden in Essex, and leaves out Peterborough, Huntingdon, March and Wisbech, which are all in the county.
Since where you live barely moves the odds and how the car has been looked after moves them a great deal, the thing worth doing is finding out where your own car actually stands, which is what a full service is for.
Find out where your own car stands
Tell us the car 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, which cars fail most around Cambridge, our pre-MOT check.