Since October 2017, the UK uses four write-off categories: Cat A (scrap entirely, not even for parts), Cat B (break for parts only, body shell must be destroyed), Cat S (structural damage, can be legally repaired and re-registered), and Cat N (non-structural damage, can be repaired and re-registered). Cars from before October 2017 may still be marked with the older Cat C or Cat D codes on historical records.
At a glance
| Category | Meaning |
|---|---|
| Cat A | Scrap only — must be crushed, no parts may be reused |
| Cat B | Body shell scrapped; other parts may be salvaged and resold |
| Cat S (structural) | Structural/chassis damage; repairable and can return to the road if done properly |
| Cat N (non-structural) | Non-structural damage (e.g. bodywork, electrics); repairable and roadworthy |
| Cat C / Cat D (pre-Oct 2017) | Older equivalents roughly matching today's Cat S and Cat N |
Why the categories changed in 2017
The older A/B/C/D system was replaced from October 2017 with A/B/S/N, mainly to make clear which category involves structural damage (S) versus damage that's serious enough for the insurer to write the car off financially but doesn't affect the structural integrity (N) — for example, a stolen-and-recovered car with a damaged interior, or a car written off mainly due to expensive electronics/airbag replacement costs relative to its value.
What each category means for a buyer
- Cat A: the vehicle must be crushed in its entirety — if you ever see one advertised for sale or parts, that's illegal and a serious red flag.
- Cat B: the bodyshell must be destroyed, but mechanical parts, electronics and other components can legally be sold on individually — you should never see a whole Cat B car offered for road use.
- Cat S: the car had structural (chassis/frame) damage but can be professionally repaired, inspected and legally returned to the road with a rebuilt/altered vehicle inspection.
- Cat N: the car had non-structural damage — often cosmetic, electrical or related to expensive components — and can be repaired and returned to the road without the same structural scrutiny as Cat S.
Should you buy a Cat S or Cat N car?
Plenty of Cat N cars are perfectly good to drive — insurers sometimes write off relatively minor damage on older or lower-value cars simply because repair costs exceed the car's market value, not because the damage was severe. Cat S cars need more scrutiny since structural repairs, if done poorly, can affect crash safety — ask for full repair documentation, invoices, and ideally an independent engineer's report before buying, and expect to pay noticeably less than an equivalent non-written-off example.
How to check a car's write-off history
- Run a paid vehicle history (HPI-style) check using the registration number — this is the standard way to reveal write-off category, since it isn't shown on the V5C.
- Ask the seller directly and compare their answer against the check result — undisclosed write-off history is a common source of used-car disputes.
- Request repair invoices, photos, and any engineer's report for Cat S vehicles specifically.
- Get an independent inspection before committing, particularly for Cat S cars or any car with an unusually low asking price relative to similar listings.
Insurers may decline to insure a Cat S or Cat N car at all, or only offer third-party cover, and its resale value will be permanently lower than an equivalent non-written-off example — factor this into any offer you make.
Frequently asked questions
Can a Cat S car be driven on the road legally?
What's the difference between Cat S and Cat N?
Is it illegal to sell a Cat A or Cat B car for road use?
How do I find out if a used car has a write-off category?
Will a Cat N or Cat S car be harder to insure?
Sources & further reading
- ABI – guide to vehicle salvage categories
- GOV.UK – buying a written-off vehicle
- Which? – buying a Cat S or Cat N car
Figures, prices and policy details were current at the last-updated date above. Automotive pricing, incentives and regulations change frequently — verify time-sensitive details with the linked primary sources. Read our editorial policy and fact-checking standards.
