Mazda
BT 50
1,475 MOT tests analysed. runs below the UK fleet average — here's where BT 50s pass, fail, and end up on the retest sheet.
That's 8.5 points below the UK fleet average across our 1,984 tracked models — buyers should expect more first-time fails than the typical UK car.
Pass
69.0%
Pass-after-fix
7.9%
Fail
22.3%
Avg miles
116,014
Pass + Pass-after-fix + Fail = 100%
Some examples of this model are borderline — a small number of diesels were certified Euro 6 before September 2015. Check your registration on the government's ULEZ checker to be certain. Daily charges if driven in the zone: London £12.50 · Birmingham £8.00 · Bristol £9.00 .
The picture
Bt-50: a below-average pass rate worth digging into
Across 1,268 MOT tests, the Bt-50 returns 66.8% first-time pass — well below the UK fleet average. The single most-logged Major fail is a corroded brake pipe. A number-plate lamp out and windscreen damage round out the top three. Average tested mileage sits at 112,578, which is the lens to read those failure rankings through. If you own one and the next test is close, the ranked list below is a sensible pre-test checklist.
ABI Insurance Group
Group 26–34
Above average — worth comparing quotes before buying. Lower groups cost less to insure; UK fleet average is around Group 22.
Source: ABI Group Rating Panel · administered by Thatcham Research · groups cover standard variants; performance trims may sit higher. Browse all insurance groups →
26–34
out of 50
Top ten reasons for rejection.
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- 01
Headlamp reflector or lens slightly defective
90 occurrences · 6.1% of tests
- 02
A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning
86 occurrences · 5.8% of tests
- 03
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
70 occurrences · 4.7% of tests
- 04
A rear registration plate lamp or light source missing or inoperative in the case of multiple lamps or light sources
65 occurrences · 4.4% of tests
- 05
Brake pipe damaged or excessively corroded
62 occurrences · 4.2% of tests
- 06
A transmission shaft constant velocity joint boot severely deteriorated
59 occurrences · 4.0% of tests
- 07
The strength or continuity of the load bearing structure within 30cm of any sub-frame, spring or suspension component mounting (a 'prescribed area') is significantly reduced or inadequately repaired
52 occurrences · 3.5% of tests
- 08
A suspension joint dust cover severely deteriorated
45 occurrences · 3.1% of tests
- 09
Body, cab or chassis excessively corroded at a mounting point
42 occurrences · 2.8% of tests
- 10
An obligatory rear fog lamp missing, or a front or rear fog lamp inoperative or in the case of a multiple light source more than 1/2 not functioning
34 occurrences · 2.3% of tests
Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.
Worst-case fix budget · top 3 failures
£58–£205
If every one of this BT 50's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →
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Build your own retest budget.
Tools that pre-empt a retest.
Picked against this car's top failure patterns. Affiliate links to Amazon UK — we earn a small cut at no cost to you. Disclosed up-front, doesn't shape the data.
Item 01 · Amazon UK
Headlight restoration kit
Yellowed lenses fail the light-output test. A restoration kit lifts the haze in an afternoon for £20.
Search Amazon UK
Item 02 · Amazon UK
H7 / W21W bulb pack
A spare-bulb kit lives in the boot. Test morning is not the time to find your stop-lamp's gone.
Search Amazon UK
My Motor World · affiliate
Parts & supplies for this fix
Affiliate links — small commission, no extra cost to you.
Draper
Draper Drain Plug Key, 3/8 Square x 3/8 Sq. Dr.
£15.39
View at My Motor World →
Hycote
Hycote Mazda Silver Stone Double Acrylic Spray Paint 150ml
£6.59
View at My Motor World →
Autotek
Autotek Mazda Arctic White 300ml
£14.29
View at My Motor World →
Autotek
Autotek Mazda Brilliant Black 300ml
£14.29
View at My Motor World →
Click Mechanic · affiliate
Book a mobile mechanic
Affiliate links — small commission, no extra cost to you.
Mobile mechanic · UK-wide
Book a mechanic at your door.
Fixed-price quotes upfront. No garage needed. Click Mechanic sends a vetted local mechanic to you — home, work, or roadside.
Recall history
2 UK recalls on record.
The BT 50 has 2 official UK vehicle recalls covering defect details, remedies, and affected build dates.
Buying or keeping a BT 50?
Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.
If you own a BT 50 and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.