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Know Your MOT research: data studies
Original rankings computed from our own compatibility and specification dataset. Every figure is a real count from the data, with the sample size shown and the method stated on each study. The tables are free to cite and republish with a link.
Data as of September 2026.
Least reliable cars: the models that fail their MOT most41.9% · The Rover 115 has the highest MOT failure rate of any high-volume carMost reliable cars: the highest MOT pass rates95.3% · The Bentley Bentayga has the highest MOT pass rate of any high-volume carHow MOT pass rate falls with a car's age2.1x · MOT failure rate rises steeply with a car's ageMost reliable used cars under 10 years old95.9% · Among used cars 3 to 10 years old, the Ferrari 488 has the highest MOT pass rateWhat cars fail their MOT on, by area19.8% · Lamps & electrical is the single most common MOT failure area in BritainThe cars that fail most on brakes24.6% · The Mercedes-Benz 308 records the most brakes MOT defects per test of any high-volume carThe cars that fail most on emissions13.2% · The Rover Metro records the most emissions MOT defects per test of any high-volume carThe cars that fail most on tyres10.4% · The BMW I4 records the most tyres MOT defects per test of any high-volume carThe cars that fail most on suspension20.9% · The Rover 115 records the most suspension MOT defects per test of any high-volume carThe cars that fail most on lights and electrics24.0% · The Mercedes-Benz 308 records the most lights and electrics MOT defects per test of any high-volume car