Original analysis
Where cars fail their MOT, and where they don’t
Across 116 postcode areas the first-time fail rate runs from 12.2% to 33.6%. We checked whether older cars or higher mileage explain the gap. They don’t.
Lowest fail rates
| Area | Fail | Median age | vs its age |
|---|---|---|---|
| E London | 12.2% | 9 | -44.5% |
| IG Ilford | 12.2% | 9 | -42.6% |
| UB Hayes | 12.2% | 10 | -46.2% |
| RM Romford | 12.8% | 9 | -41.2% |
| N London | 13.6% | 10 | -40.6% |
| EN Enfield | 14% | 9 | -36.2% |
| HA Wembley | 14% | 9 | -37.1% |
| NW London | 14.3% | 8 | -29.7% |
| SL Slough | 14.4% | 10 | -36.9% |
| DA Dartford | 14.5% | 9 | -32.3% |
Highest fail rates
| Area | Fail | Median age | vs its age |
|---|---|---|---|
| KY Kirkcaldy | 33.6% | 9 | +59.4% |
| DD Dundee | 32.4% | 9 | +58.9% |
| PL Plymouth | 31.2% | 11 | +27.1% |
| TR Truro | 31.1% | 11 | +26.7% |
| EX Exeter | 30.4% | 11 | +24.8% |
| AB Aberdeen | 29.6% | 8 | +47.9% |
| TQ Newton Abbot | 29.6% | 12 | +17.5% |
| LD Brecon | 29.3% | 11 | +22.2% |
| SP Salisbury | 28.8% | 11 | +20.6% |
| LN Lincoln | 28.6% | 10 | +26.6% |
What we measured
Every class 4 first-attempt MOT in 2025, 30,851,141 of them, grouped by the postcode area recorded against the test. Areas with fewer than 20,000 tests are left out. The national fail rate was 22.6%.
Kirkcaldy (KY) fails 33.6% of cars. Four east London areas fail 12.2% to 12.8%. That is close to a threefold difference between places in the same country under the same test standard.
Age does not explain it
Older cars fail more, so the obvious answer is that high-failure areas run older cars. We tested it by taking the national fail rate for each vehicle age and applying it to each area’s own age mix, then comparing what actually happened with what that mix predicts. The “vs its age” column above is that comparison.
Kirkcaldy and east London both have a median tested car of 9 years old. Kirkcaldy still fails 59% more often than its age mix predicts. East London fails 44% less. Age is not doing the work.
Nor does mileage
The correlation between an area’s median mileage at test and its fail rate is 0.16, which is weak. Kirkcaldy’s median tested car has 63,296 miles against east London’s 77,217. Fewer miles, nearly triple the failures.
Corrosion is part of it
We tagged every DVSA defect code whose wording involves corrosion, 364 of them, and counted the share of failed tests in each area where at least one was recorded.
| Area | Share of failures involving corrosion |
|---|---|
| TR Truro | 16.4% |
| KY Kirkcaldy | 13.4% |
| PL Plymouth | 12.7% |
| AB Aberdeen | 12.7% |
| DD Dundee | 12.2% |
| LS Leeds | 9.4% |
| CF Cardiff | 7.5% |
| M Manchester | 7.1% |
| B Birmingham | 6.2% |
| UB Hayes | 2.8% |
| IG Ilford | 2.5% |
| E London | 2.2% |
Every postcode area
All 116 areas with at least 20,000 tests, lowest fail rate first. The place name is the town most of that area’s MOT stations sit in, and links to its garages.
| Area | Fail rate | Median age | Median miles | vs its age |
|---|---|---|---|---|
| E London | 12.2% | 9 | 77,217 | -44.5% |
| IG Ilford | 12.2% | 9 | 65,260 | -42.6% |
| UB Hayes | 12.2% | 10 | 74,117 | -46.2% |
| RM Romford | 12.8% | 9 | 68,449 | -41.2% |
| N London | 13.6% | 10 | 70,540 | -40.6% |
| EN Enfield | 14% | 9 | 63,491 | -36.2% |
| HA Wembley | 14% | 9 | 67,553 | -37.1% |
| NW London | 14.3% | 8 | 57,874 | -29.7% |
| SL Slough | 14.4% | 10 | 70,815 | -36.9% |
| DA Dartford | 14.5% | 9 | 61,442 | -32.3% |
| CR Croydon | 14.6% | 9 | 62,494 | -33.9% |
| SE London | 15% | 10 | 66,123 | -34.4% |
| TW Hounslow | 15.2% | 9 | 61,022 | -30.8% |
| SM Sutton | 15.5% | 10 | 62,220 | -33.6% |
| BR Orpington | 15.7% | 8 | 47,631 | -23.1% |
| LU Luton | 16.3% | 11 | 82,161 | -31.3% |
| KT Kingston Upon Thames | 16.4% | 9 | 55,681 | -25.2% |
| W London | 16.8% | 9 | 55,822 | -20% |
| B Birmingham | 17% | 10 | 73,937 | -26.5% |
| SS Basildon | 17.2% | 10 | 66,588 | -24.7% |
| SW London | 17.6% | 9 | 54,035 | -18.3% |
| CM Chelmsford | 18.7% | 9 | 64,617 | -14.1% |
| HP High Wycombe | 18.8% | 10 | 68,550 | -16.9% |
| BB Blackburn | 19% | 10 | 74,727 | -16.2% |
| ME Maidstone | 19.1% | 10 | 70,958 | -16.9% |
| AL St Albans | 19.3% | 9 | 59,551 | -10.4% |
| WV Wolverhampton | 19.6% | 10 | 69,108 | -12.9% |
| DY Stourbridge | 19.8% | 10 | 68,046 | -14.9% |
| S Sheffield | 19.8% | 10 | 71,528 | -13.4% |
| SG Stevenage | 20% | 10 | 67,067 | -10.5% |
| CV Coventry | 20% | 10 | 71,161 | -11.8% |
| RG Reading | 20.2% | 10 | 67,171 | -10.5% |
| LE Leicester | 20.3% | 10 | 73,483 | -12.2% |
| L Liverpool | 20.4% | 10 | 65,378 | -6.8% |
| MK Milton Keynes | 20.4% | 10 | 70,873 | -8.4% |
| DE Derby | 20.6% | 10 | 69,061 | -8.2% |
| BL Bolton | 20.7% | 9 | 64,609 | -3.1% |
| M Manchester | 20.9% | 10 | 72,493 | -10.3% |
| BD Bradford | 21% | 11 | 77,823 | -10.4% |
| OL Oldham | 21.3% | 10 | 68,339 | -3.1% |
| RH Crawley | 21.4% | 10 | 66,370 | -7.2% |
| DG Dumfries | 21.8% | 10 | 69,566 | -1.4% |
| WF Wakefield | 21.9% | 10 | 71,029 | -2% |
| PE Peterborough | 21.9% | 10 | 76,893 | -4.8% |
| DH Durham | 22% | 9 | 66,139 | +1.9% |
| NE Newcastle Upon Tyne | 22% | 9 | 64,392 | +2.5% |
| PR Preston | 22.2% | 10 | 65,261 | +0.5% |
| GU Guildford | 22.3% | 10 | 66,607 | -1.8% |
| SK Stockport | 22.4% | 9 | 57,392 | +4.9% |
| WR Worcester | 22.5% | 10 | 70,543 | -2.4% |
| WA Warrington | 22.5% | 9 | 60,332 | +6.4% |
| WS Walsall | 22.5% | 10 | 69,944 | -1% |
| WD Watford | 22.5% | 9 | 56,007 | +8.2% |
| CB Cambridge | 22.6% | 10 | 74,618 | -2.5% |
| HX Halifax | 22.7% | 10 | 68,426 | +1% |
| TN Ashford | 22.7% | 10 | 68,676 | -3% |
| HG Harrogate | 22.8% | 9 | 56,885 | +11.1% |
| CW Crewe | 23% | 9 | 62,494 | +6.3% |
| OX Oxford | 23.1% | 10 | 73,271 | -0.1% |
| CA Carlisle | 23.1% | 9 | 67,072 | +7.1% |
| TS Middlesbrough | 23.2% | 10 | 69,460 | +5.1% |
| DN Doncaster | 23.2% | 10 | 74,384 | +2.5% |
| SO Southampton | 23.4% | 10 | 70,242 | +0.6% |
| CO Colchester | 23.5% | 11 | 75,110 | -0.7% |
| KW Kirkwall | 23.5% | 10 | 67,389 | +5.9% |
| IP Ipswich | 23.5% | 11 | 77,819 | -1.3% |
| TD Berwick Upon Tweed | 24% | 9 | 65,778 | +13.2% |
| SY Shrewsbury | 24% | 10 | 73,659 | +3.2% |
| HR Hereford | 24.1% | 11 | 76,870 | +0.7% |
| LA Kendal | 24.1% | 10 | 69,380 | +5.3% |
| NN Northampton | 24.2% | 10 | 72,864 | +8.1% |
| WN Wigan | 24.3% | 10 | 65,416 | +10% |
| CT Canterbury | 24.4% | 11 | 71,842 | +3.1% |
| LS Leeds | 24.5% | 10 | 67,010 | +11.1% |
| G Glasgow | 24.5% | 8 | 55,504 | +25.4% |
| NG Nottingham | 24.7% | 10 | 70,868 | +7.7% |
| TF Telford | 24.8% | 10 | 75,739 | +6.5% |
| SN Swindon | 24.9% | 10 | 72,471 | +8% |
| NR Norwich | 25% | 11 | 75,266 | +4.5% |
| DL Darlington | 25.2% | 10 | 69,645 | +15.3% |
| LL Wrexham | 25.3% | 11 | 77,932 | +5.7% |
| HD Huddersfield | 25.3% | 9 | 61,322 | +18.6% |
| KA Ayr | 25.5% | 8 | 59,712 | +27.6% |
| ST Stoke on Trent | 25.6% | 10 | 66,667 | +15% |
| CH Chester | 25.7% | 10 | 66,502 | +14.8% |
| NP Newport | 26% | 10 | 74,759 | +13.2% |
| ML Hamilton | 26.2% | 8 | 56,469 | +37% |
| SA Swansea | 26.2% | 10 | 71,075 | +15.2% |
| YO York | 26.2% | 10 | 67,379 | +18.5% |
| IV Inverness | 26.4% | 9 | 64,399 | +27.6% |
| BH Poole | 26.5% | 11 | 69,210 | +10% |
| FK Stirling | 26.7% | 8 | 56,733 | +36.8% |
| GL Gloucester | 26.7% | 11 | 74,344 | +12.6% |
| CF Cardiff | 26.9% | 10 | 69,981 | +20.4% |
| PA Paisley | 27.1% | 8 | 55,551 | +36.9% |
| SR Sunderland | 27.2% | 9 | 64,414 | +27.2% |
| EH Edinburgh | 27.3% | 9 | 56,343 | +34.9% |
| DT Dorchester | 27.3% | 12 | 80,428 | +6.8% |
| PO Portsmouth | 27.5% | 11 | 71,143 | +14.5% |
| TA Taunton | 27.5% | 11 | 79,733 | +11.3% |
| HU Hull | 27.6% | 10 | 67,082 | +24.5% |
| FY Blackpool | 27.7% | 10 | 65,935 | +20.7% |
| BN Brighton | 27.8% | 11 | 67,519 | +16.9% |
| PH Perth | 28.2% | 9 | 61,965 | +39.5% |
| BA Yeovil | 28.4% | 11 | 74,260 | +18.5% |
| BS Bristol | 28.6% | 10 | 70,033 | +23.1% |
| LN Lincoln | 28.6% | 10 | 71,090 | +26.6% |
| SP Salisbury | 28.8% | 11 | 77,633 | +20.6% |
| LD Brecon | 29.3% | 11 | 78,451 | +22.2% |
| TQ Newton Abbot | 29.6% | 12 | 75,852 | +17.5% |
| AB Aberdeen | 29.6% | 8 | 57,426 | +47.9% |
| EX Exeter | 30.4% | 11 | 76,232 | +24.8% |
| TR Truro | 31.1% | 11 | 78,253 | +26.7% |
| PL Plymouth | 31.2% | 11 | 79,350 | +27.1% |
| DD Dundee | 32.4% | 9 | 59,315 | +58.9% |
| KY Kirkcaldy | 33.6% | 9 | 63,296 | +59.4% |
Truro reaches 16.4% and Kirkcaldy 13.4%, against 2.2% in east London. Coastal air and winter road salt are the obvious reading, and the pattern fits: Cornwall, Devon, Fife, Dundee and Aberdeen all sit near the top.
It only accounts for part of the gap though. Strip out every corrosion-involved failure and Kirkcaldy still lands near 29%, well above east London’s 12%. So corrosion is a real regional effect and a minority of the story.
What we have not tested
Several things could drive the rest, and we have not measured any of them, so treat these as open questions rather than findings. Tester strictness may vary between areas. Spend on maintenance varies with income. Urban cars of the same age may simply be in better condition, and London’s emissions zones have reshaped which cars live there in ways that age alone will not capture.
If you want to check a single vehicle rather than an area, the MOT history check shows its own record, and the model pages show what each model tends to fail on.
First-attempt class 4 tests, 2025, from DVSA’s anonymised MOT data (Open Government Licence v3), retrieved 2026-09-12. Area names are the town most MOT stations in that postcode area sit in.