The Ford Fiesta is the most-tested car in the UK MOT record. In 2024 it generated 2,488,311 tests — more than any other model. That scale means when a cohort goes bad, the numbers are brutal.
The cohort gap
Split the Fiesta’s fleet into registration-year bands and the picture sharpens fast.
Cars registered before 2018 — the overwhelming bulk of the fleet at 2,236,442 tests — passed at 70.65%. The fail rate was 22.64%, with another 6.14% picking up advisory-only marks (pass with rectification, or PRS). That means roughly one in three pre-2018 Fiestas left the MOT bay either failed or with items that need attention soon.
Move to the 2018–2020 band and the numbers flip. Those 245,203 tests returned an 87.15% pass rate — 16.5 percentage points higher. The 2021+ cohort sits at 88.04%, though only 6,666 tests have reached MOT age so the sample is thin.
The swing of 17.39 percentage points between the worst and best cohorts is not unusual for a high-volume mass-market car. What makes the Fiesta notable is the sheer weight behind the bottom number. Two million failing or advisory tests is a maintenance problem operating at national scale.
What’s going wrong on older cars
The pre-2018 failure list reads like a suspension audit. The single biggest reason for failure across that cohort was suspension pins, bushes or joints excessively worn — recorded 79,482 times. Steering ball joints with excessive wear came in at 48,129. Suspension joint dust covers severely deteriorated added another 43,911 hits. Springs fractured or seriously weakened: 37,164.
That pattern points at age and mileage rather than any design fault. The average mileage at test for pre-2018 Fiestas was 78,109 miles — well into the range where rubber bushes degrade and ball joints loosen. UK roads, particularly urban routes the Fiesta was designed for, accelerate that wear.
Lighting failures were the second cluster. Stop lamps missing or inoperative: 63,968 failures. Rear registration plate lamps: 42,808. Generic lamp failures: 39,072. These are cheap fixes — a bulb or a connector — but they catch owners off guard because they’re often invisible until the examiner checks.
Tyre tread was fourth overall at 46,837 failures. On a car averaging 78,000 miles, that figure is almost expected. Less expected was windscreen damage at 34,021, which suggests a lot of pre-2018 Fiestas are being run with chips that have spread beyond the acceptable threshold.
The newer cars aren’t immune
The 2018–2020 cars fail at a much lower rate, but the failure modes shift rather than disappear. Tyre tread tops the list at 4,430 — proportionally smaller but still significant. Brake linings or pads worn below 1.5mm added 3,337 failures, and tyre damage (structural) came in at 2,391.
At an average of 36,101 miles at test, these cars are hitting their first round of consumable replacements. Brakes and tyres are predictable. The suspension deterioration seen on older cars hasn’t yet had time to develop — but at the rate the pre-2018 cohort is failing, owners of 2018-vintage Fiestas have a window of perhaps three to four years before similar patterns emerge.
What this means if you own one
A pre-2018 Fiesta going into its next MOT should have the front suspension checked thoroughly beforehand. Not just a visual — a proper check of the ball joints and wishbone bushes under load. The failure count is too consistent to treat as bad luck.
If the car is approaching 80,000 miles, add the following to any pre-MOT list:
- All four tyres for tread and sidewall condition
- Stop lamps and rear registration plate lights (often missed in weekly checks)
- Windscreen for chips or cracks at or near the swept area
- Front brake pads if the service history has a gap
The 70.65% pass rate is an average. Maintained pre-2018 Fiestas pass fine. Neglected ones are dragging the whole cohort down — and with 2.2 million of them in the test queue, that weight adds up.
Fleet context
The Fiesta’s overall 2024 pass rate of 72.32% sits below the passenger car average, but the age profile of its fleet explains most of that gap. No other model has volume this high concentrated in cohorts this old. When Ford ended Fiesta production in 2023, it locked in the fleet’s age trajectory — no new registrations will pull the average up. The pre-2018 cohort will dominate the test queue for years to come, and its pass rate is unlikely to improve as the cars age further.
The data is a record of where the fleet is now. What it tells you is that the Fiesta’s MOT statistics are going to get harder to read, not easier, over the next five years.