What Do Cat S and Cat N Mean? UK Write-Off Categories Explained
Browsing UK listings you'll come across 'Cat S' or 'Cat N' — official categories showing that an insurer once declared the car a write-off. A write-off marker doesn't automatically mean 'stay away'; but you should never buy without knowing exactly what it means. This guide explains the four categories, the price impact and how to buy safely.
The four categories: A, B, S, N
When repair costs are high relative to the car's value, the insurer declares it a write-off and assigns a category:
- Cat A — Scrap. The whole car must be destroyed; even parts cannot be sold. It can never return to the road.
- Cat B — Break. The shell must be destroyed, but sound parts may be stripped and sold. The car cannot return to the road.
- Cat S — Structural damage. The chassis or structural frame was damaged; it can be repaired, re-registered and driven again.
- Cat N — Non-structural damage. Electrics, body panels, interior — non-structural damage; the car can return to the road after repair.
Is buying a written-off car a good idea?
Cat S/N cars sell noticeably below clean equivalents, and the discount is permanent: you'll have to offer the same discount when you sell. A properly repaired Cat N (hail damage, a stolen bumper) can be a very sensible buy; a badly repaired Cat S is a safety risk.
The critical question is not the marker itself but the quality of the repair. Structural repairs (Cat S) demand especially careful inspection: chassis measurement, weld points, panel gaps and paint depth should all be checked on site.
The real danger: hidden write-offs
Some written-off cars are offered at 'clean' prices with the marker never mentioned. Buyers in Cyprus and Malta are the primary target of this game, because most don't know how to query UK records.
The protection is simple: run an HPI check on every car. The write-off marker, its date and category appear in seconds. An HPI check is standard in every ThinCheck package; our on-site inspection also detects repair traces with paint-depth measurement — even when the seller says nothing.
Checklist for buying a written-off car
- Get the category and marker date from an HPI check
- Ask for repair invoices and photos
- An on-site inspection is essential: chassis, weld traces, panel alignment, paint depth
- For Cat S, confirm re-registration paperwork is complete
- Make sure the price sits at least 20–30% below a clean equivalent
- Ask about insurance costs upfront — some insurers load premiums on written-off cars
Is there a marker? Is the repair sound? Let us check
An HPI check is standard in all our packages. On site we assess the repair quality and give you a clear verdict: buy, negotiate or walk away.
Request an Inspection