The picture
Mii: above-average pass rates, with caveats
Across 20,012 MOT tests, the Mii returns 81.2% first-time pass — above the UK fleet average. The single most-logged Major fail is a binding brake. Tyre tread under the limit and wipers that don't clear the screen round out the top three. Average tested mileage sits at 47,727, which is the lens to read those failure rankings through. If you own one and the next test is close, the ranked list below is a sensible pre-test checklist.
Top ten reasons for rejection.
- 01
Significant brake effort recorded with no brake applied indicating a binding brake
446 occurrences · 2.2% of tests
- 02
Tyre tread depth not in accordance with the requirements
389 occurrences · 1.9% of tests
- 03
Wiper blade missing or obviously not clearing the windscreen
327 occurrences · 1.6% of tests
- 04
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
262 occurrences · 1.3% of tests
- 05
An SRS malfunction indicator lamp (MIL) indicates a system malfunction
237 occurrences · 1.2% of tests
- 06
Wiper blade defective
207 occurrences · 1.0% of tests
- 07
Fuel system leaking, or missing or ineffective filler cap
206 occurrences · 1.0% of tests
- 08
a brake lining or pad worn below 1.5mm
193 occurrences · 1.0% of tests
- 09
A suspension pin, bush or joint excessively worn
179 occurrences · 0.9% of tests
- 10
A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning
169 occurrences · 0.8% of tests
Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.
Worst-case fix budget · top 2 failures
£80–£140
If every one of this Mii's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →
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Build your own retest budget.
Tools that pre-empt a retest.
Picked against this car's top failure patterns. Affiliate links to Amazon UK — we earn a small cut at no cost to you. Disclosed up-front, doesn't shape the data.
Item 01 · Amazon UK
Digital tyre-tread depth gauge
Five quid for a gauge beats £150 for a retest. UK MOT minimum is 1.6mm — most testers fail anything below 2mm to be safe.
Search Amazon UK
Item 02 · Amazon UK
Bosch Aerotwin wiper blades
Cheap wipers fail the test on smear streaks. Bosch Aerotwins last a winter and clear a screen properly.
Search Amazon UK
Buying or keeping a Mii?
Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.
If you own a Mii and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.