MG B/Gt MOT pass rate & common failures
Across 34 model years and 1,199 tests, the MG B/Gt passes its MOT 80.0% of the time. Against all cars of a similar age (17.2% fail rate), the B/Gt comes out 2.8pp worse. Its most common failure areas are lighting & signalling, emissions & environmental and brakes.
What the MOT record shows
No single area dominates — lighting & signalling (11.5%) and emissions & environmental (9.5%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are non catalyst emissions, washers and headlamp aim — non catalyst emissions alone was recorded 124 times.
Mileage matters less than usual here: the B/Gt fails 19.7% of the time in the 0-30k band and 23.1% at 90-120k, a spread of only 3.3 points.
Suspension is the most common advisory, noted on 18.4% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 21.7% in 2021 to 18.6% in 2025, as the worst-kept examples leave the fleet.
How it compares
By model year
Every B/Gt model year with a usable sample. Years with their own detailed report are linked.
| Year | Tests | Pass rate | Fail rate | Most common failure |
|---|---|---|---|---|
| 1980 | 465 | 79.3% | 20.6% | Lighting & signalling |
| 1981 | 633 | 79.8% | 20.2% | Emissions & environmental |
Most common failures (all years)
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 11.5% | 138 |
| 2 | Emissions & environmental | 9.5% | 114 |
| 3 | Brakes | 6.3% | 76 |
| 4 | Visibility | 6.0% | 72 |
| 5 | Suspension | 5.3% | 64 |
| 6 | Body, structure & corrosion | 3.1% | 37 |
| 7 | Steering | 2.9% | 35 |
| 8 | Seat belts & restraints | 0.8% | 9 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Non catalyst emissions | 124 |
| 2 | Washers | 61 |
| 3 | Headlamp aim | 47 |
| 4 | Position lamp | 43 |
| 5 | Component mounting prescribed areas | 38 |
| 6 | Rear fog lamp | 37 |
| 7 | Service brake performance | 36 |
| 8 | Service brake imbalance | 32 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Suspension | 18.4% | 221 |
| 2 | Emissions & environmental | 15.9% | 191 |
| 3 | Brakes | 8.6% | 103 |
| 4 | Tyres | 6.6% | 79 |
| 5 | Other defects | 6.2% | 74 |
| 6 | Body, structure & corrosion | 5.1% | 61 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 0-30k | 309 | 19.7% |
| 30-60k | 340 | 16.2% |
| 60-90k | 444 | 22.3% |
| 90-120k | 104 | 23.1% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 382 | 21.7% |
| 2022 | 219 | 16.9% |
| 2023 | 221 | 20.8% |
| 2024 | 189 | 20.6% |
| 2025 | 188 | 18.6% |
What to check before buying a MG B/Gt
- Lighting & signalling (11.5% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Emissions & environmental (9.5% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
- Brakes (6.3% of tests): Pads/discs are routine wear; binding, imbalance or corroded pipes are more serious — test for pulling under braking. Typical repair: £100–£350 per axle.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
What is the MOT pass rate for the MG B/Gt?
80.0% of the 1,199 MG B/Gt MOT tests in this dataset passed, a 20.0% fail rate, across model years 1980–2013.
What does the MG B/Gt most often fail its MOT on?
Lighting & signalling, recorded in 11.5% of tests, then emissions & environmental (9.5%).
How much does mileage affect B/Gt MOT results?
Fail rates run at 19.7% for cars in the 0-30k band and 23.1% for 90-120k, a 3.3-point difference.
Methodology & source. Based on 1,199 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-27. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.