MOT Failure Rates by Brand: Which Car Manufacturers Are Most Reliable?

When you're shopping for a used car, the manufacturer's badge matters. Not for prestige, but for MOT pass rates - the most reliable predictor of whether you'll be hit with a £600 repair bill or sail through for the price of the test fee.

We've analysed over 132 million official MOT records from the DVSA to settle the arguments once and for all. Which brands build cars that stay roadworthy? Which are maintenance nightmares disguised in premium leather?

The results are surprising. Premium badges don't guarantee reliability, and some budget brands punch well above their weight. Here's what the data really says.

Abarth: The Unlikely Reliability Champion

Abarth - the hot-blooded Italian performance brand - sits at the top of our rankings. Yes, really. The 124 Spider, essentially a rebodied Mazda MX-5 with a turbocharged Fiat engine, dominates the top positions with reliability scores between 566 and 653 out of 1000.

The secret? These are garage queens. The 124 Spider manual averages just 2,912 miles annually - owners treat them as weekend toys, not daily transport. Low mileage means less wear, fewer faults, and cleaner MOT sheets.

The hot hatches fare worse. The Abarth 595 and 695 models - tuned Fiat 500s - score reliability ratings between 431 and 548. These are driven harder and more frequently, with annual mileages around 5,000 miles. The combination of a small, stressed engine and enthusiastic driving shows up in the MOT bay: brake discs, pads, and suspension bushes need attention more frequently than the low-mileage Spiders.

Bottom line: Abarth's strong showing is about usage patterns, not engineering excellence. Buy a 124 Spider as a summer toy and you'll likely enjoy trouble-free motoring. Buy a used 595 that's been thrashed around town and expect bills.

Alfa Romeo: Beauty and the Breakdown

Alfa Romeo's reputation for beautiful but fragile cars is only half deserved. The data splits the range cleanly: their modern performance models are solid, the older mainstream cars are money pits.

The Stelvio SUV and Giulia saloon from 2019-2020 achieve reliability scores around 600-660, with pass rates consistently above 87%. These cars rack up serious miles - the diesel Stelvios average over 9,000 miles annually - yet hold up well. The first MOT pass rate closely matches the overall rate, suggesting they age gracefully rather than falling apart after three years.

The 4C supercar is even better, scoring 653 with a 91.5% pass rate despite being a decade old. But again, usage is key: these rare mid-engined exotics cover barely 1,200 miles a year. They're investments, not transport.

The story is clear: Alfa's premium models - Giulia, Stelvio - are genuinely well-engineered. The budget models built on older platforms - Giulietta, MiTo - inherited Fiat's cost-cutting and are showing their age badly. If you're buying Alfa, spend more or walk away.

Aston Martin: When Money Buys Reliability

Aston Martin's MOT performance is exactly what you'd expect from a brand charging £150,000+ for a car: exceptional. The 2018 Vanquish achieves a 757 reliability score - the highest in our dataset - with a 97.5% pass rate.

Every Aston we analysed scores above 659, with pass rates above 94%. The DB11, DBS, and Vantage models sail through MOTs with barely a mention of serious defects. The dangerous defect rate across the range sits below 3% - negligible compared to mainstream brands.

Why so good? Three factors. First, these cars cover minimal miles - typically 1,500-2,500 annually. They're collector cars, not daily drivers. Second, owners who can afford a £200,000 Aston can afford preventative maintenance. Third, hand-built quality at this price point means components are genuinely better engineered.

The only recurring issue? Tyres. Aston's fit Pirelli P Zeros as standard, and they crack and perish when cars sit unused. But that's a wear item, not a reliability concern.

Verdict: If you can afford to run an Aston Martin, you'll find it reliable. Just not cheap.

Adria and Aixam: The Budget Warning Signs

At the other end of the spectrum, budget brands reveal how false economies work. Adria motorhomes score reasonably well (603-655) but are essentially leisure vehicles tested annually with minimal use - around 3,000 miles per year. Not comparable to daily drivers.

Aixam microcars are the real concern. These tiny French city cars, popular as mobility vehicles, score between 102 and 276 for reliability. The 2014 Crossline manages just a 74.1% pass rate with a dangerous defect rate of 43.1%.

The pattern is clear: ultra-budget engineering means ultra-expensive repairs. An Aixam might cost £10,000 new, but keeping it roadworthy will drain your wallet faster than a decade-old BMW.

What the Numbers Actually Tell You

MOT failure rates are not pure engineering quality metrics. They're a combination of build quality, usage patterns, owner behaviour, and age. A 95% pass rate on a three-year-old car driven 2,000 miles annually tells you nothing about how it will perform at age eight with 60,000 miles.

The most revealing metric isn't the pass rate - it's the comparison between first MOT pass rate and overall pass rate. When these numbers diverge significantly, the car is degrading faster than average. The 2019 Abarth 695, for example, drops from 82.8% first MOT pass to 88.9% overall - it's actually improving as owners address early issues. That's unusual.

Dangerous defect rates matter more than overall pass rates. A car that fails for a worn tyre is inconvenient. A car that fails for corroded brake pipes or failed suspension components is actively dangerous. The Alfa Romeo Giulia diesel models show dangerous defect rates above 50% - one in two has had a critical safety failure flagged.

Annual mileage provides context. Low-mileage exotic cars score well because they're barely used. High-mileage diesel saloons that maintain strong scores despite covering 70,000-90,000 miles are genuinely well-engineered.

How to Use This When Buying

When you're viewing a used car, pull up its MOT history on PlateInsight before you hand over any money. The national statistics tell you what to expect from the model. The individual car's history tells you if this specific example is a good one or a nightmare.

Look for patterns in the MOT history. A car that's failed multiple times for the same component - say, suspension bushes or brake discs - suggests either poor maintenance or a fundamental weakness in that area. A car with clean passes and only advisory notices for minor wear items is a much safer bet.

Compare the car's mileage to the model average. An Abarth 595 with 40,000 miles has been driven twice as hard as typical - expect more wear. A Giulia diesel with 50,000 miles has been driven gently compared to the 70,000-mile average - potentially a better buy.

Don't ignore the defects list. If every example of a model shows 'suspension arm bush worn' at around 50,000 miles, budget for that repair when buying. If brake discs appear in 20% of MOT tests, factor in a set of discs and pads within the next 12 months.

The brands at the top of our rankings - Abarth, Alfa Romeo's premium models, Aston Martin - deserve their positions for different reasons. Abarth benefits from low usage, Alfa's modern engineering is solid, Aston's quality is genuine. The brands at the bottom - older Alfa Romeos, budget microcars - have earned their poor reputations through consistent mechanical issues.

Use the data, but understand what it's telling you. A 90% pass rate on a car driven 3,000 miles annually is not comparable to a 90% pass rate on a car driven 9,000 miles annually. Context matters.

The badge on the boot matters less than how the car's been used and maintained. A well-cared-for Alfa Romeo Giulia will outlast a neglected Aston Martin. But the statistics give you the odds: some models are engineered to last, others aren't.

Before you buy any used car, check its complete MOT history on PlateInsight. We give you 5 free vehicle checks - no card required - so you can see exactly what you're buying. Enter a registration plate and we'll pull the full MOT record, plus market value, spec, and more. Don't gamble with a £10,000 purchase based on a dealer's promises.

The cars that top our rankings do so for different reasons - low usage, excellent engineering, or obsessive maintenance. The cars at the bottom share one trait: they cost more to keep roadworthy than they're worth. Choose wisely.