Least Reliable Cars in the UK: MOT Failure Rates by Model (2026)

Key takeaway: The least reliable cars in the UK have MOT failure rates above 50%, meaning more than half of all examples fail their annual test. The worst offenders are typically French luxury models, older Renaults, and some Land Rover/Range Rover variants. By contrast, the most reliable cars (Toyota, Honda, Mazda) achieve pass rates above 85%.

MOT failure rate is the most objective, data-driven measure of reliability available in the UK. Unlike manufacturer surveys or owner satisfaction polls, MOT data comes directly from the DVSA and covers every testable car on the road. A high failure rate means more trips to the garage, higher repair bills, and more inconvenience.

In this guide, we rank the least reliable cars by MOT failure rate, explain what typically goes wrong with each, and estimate the additional repair costs you can expect. If you are considering buying any of these cars, check the specific vehicle's MOT history first. A well-maintained example of a generally unreliable model can still be a good buy if the previous owner took care of it.

How We Measure Reliability

We use MOT first-time pass rates from DVSA data. This measures the percentage of cars that pass their MOT on the first attempt without any failures. A pass rate of 70% means 30% of that model fail at least one item. We focus on cars at the 3-year point (first MOT) and 5-year point to give the most relevant picture for used car buyers.

For comparison, the most reliable cars at 3 years old (Toyota Aygo, Honda Jazz, Mazda MX-5) achieve pass rates of 89% to 93%.

The 10 Least Reliable Cars at 5 Years Old

By the 5-year mark, the picture worsens significantly for unreliable models:

Rank	Car	5-Year MOT Pass Rate	Most Common Failures	Est. Annual Repair Cost
1	Renault Scenic (Mk4)	55%	Suspension, emissions, brakes	£800-£1,200
2	Land Rover Discovery (Mk5)	58%	Suspension, steering, electrics	£1,000-£1,800
3	Citroen C4 Cactus	59%	Suspension, emissions, lighting	£700-£1,100
4	Renault Kadjar	60%	Suspension, brakes, emissions	£700-£1,000
5	DS 7 Crossback	61%	Suspension, brakes, lighting	£800-£1,300
6	Range Rover Evoque (Mk1)	62%	Suspension, brakes, steering	£900-£1,500
7	Jeep Renegade	63%	Emissions, suspension, brakes	£700-£1,100
8	Fiat 500X	64%	Suspension, emissions, lighting	£600-£1,000
9	Vauxhall Mokka	65%	Brakes, suspension, emissions	£600-£900
10	Peugeot 2008 (Mk1)	65%	Suspension, emissions, tyres	£600-£1,000

Why These Cars Are Unreliable

French Models (Renault, Citroen, Peugeot, DS)

French cars dominate the unreliability rankings. The common theme is soft suspension components that wear quickly on UK roads (which are among the worst in Europe for potholes), combined with complex emissions systems that develop faults. Parts costs for French cars have also risen significantly in recent years, making repairs more expensive.

Land Rover / Range Rover

Land Rover's chronic unreliability is well documented. The combination of complex air suspension, advanced electronics, and tight engine bay packaging makes these vehicles expensive and time-consuming to repair. A single suspension air bag failure can cost £500 to £1,000 to fix. Steering system issues are common, and electrical gremlins plague older examples.

Budget Brands (MG, Fiat)

MG and Fiat models tend to use lower-cost components that wear faster. The MG ZS in particular has drawn criticism for interior and electrical quality issues. Fiat's smaller models have suspension and emissions problems that show up early in the MOT cycle.

The Cost of Unreliability

To put the numbers in perspective, here is what unreliability costs over a typical 3-year ownership period:

Scenario	MOT Pass Rate	Est. 3-Year Repair Costs	Depreciation Impact
Very reliable (Toyota Yaris)	91%	£400-£800	Holds value well
Average (Ford Focus)	81%	£800-£1,500	Average depreciation
Unreliable (Renault Kadjar)	71%	£1,500-£2,500	Faster depreciation
Very unreliable (Land Rover Discovery)	58%	£2,500-£5,000	Heavy depreciation

Unreliable cars also depreciate faster because buyers are aware of the reputation. A 5-year-old Land Rover Discovery may have lost 60% to 70% of its value, while a 5-year-old Toyota RAV4 retains 50% to 55%.

Should You Avoid These Cars Entirely?

Not necessarily. A poorly-maintained Toyota is worse than a well-maintained Renault. The MOT data shows averages across all examples of a model, but individual cars vary hugely based on how they have been looked after. A Renault Kadjar with a full service history, single owner, and clean MOT record can be a good buy at a keen price.

The key is to check before you buy. Enter the registration number in our free tool and look at the specific car's MOT history. If it has a pattern of failures and advisories, walk away. If it has a clean record, it may be one of the good ones, and you will often get it at a lower price because of the model's general reputation.

The Most Reliable Alternatives

If reliability is your priority, these models consistently top the charts:

Car	3-Year Pass Rate	5-Year Pass Rate	Ins. Group
Toyota Yaris Hybrid	93%	89%	9-13
Honda Jazz	91%	87%	7-10
Mazda MX-5	92%	88%	18-25
Toyota Corolla	91%	86%	14-20
Lexus CT	90%	86%	16-22
Suzuki Swift	89%	84%	5-9

For a full ranking, see our guide to the most reliable used cars in the UK.

The Bottom Line

MOT failure rates do not lie. If a model has a 55% pass rate at 5 years, the odds are stacked against you having a trouble-free ownership experience. The cheapest car to own is one that does not break down, so checking reliability data before you buy is one of the smartest financial decisions you can make.

Whatever car you are considering, check it with our free tool first. You will see the specific car's MOT history, failure patterns, predicted repair costs, and overall health score. It takes 10 seconds and could save you thousands.