When an insurer decides a damaged car isn't worth repairing, or isn't safe to repair, it's declared a write-off and given a category that describes how badly it was damaged. If you're buying, selling or thinking of repairing an insurance-damaged car, the category tells you what you're dealing with.
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Since 1 October 2017, UK insurers have used four write-off categories, set out by the Association of British Insurers (ABI). Two mean the car can never return to the road (Cat A and Cat B), and two mean it can legally be repaired and driven again (Cat S and Cat N).
A Category S (Cat S) car has suffered structural damage, damage to the chassis, frame or crumple zones that affects the core strength and safety of the vehicle. Examples include a bent or twisted chassis leg, a collapsed crumple zone or a damaged suspension mounting point.
A Category N (Cat N) car has suffered non-structural damage, the chassis and frame are intact, but repairing the car still cost more than the insurer was prepared to pay. Typical Cat N damage includes:
Cat N cars can legally be repaired and driven, and there's no legal requirement for a new MOT before returning to the road, but "non-structural" doesn't automatically mean minor. Steering, brakes and safety systems can be affected, so always have the repair inspected.
Category A (scrap only): the car is so badly damaged that the entire vehicle must be crushed, not even individual parts can be salvaged.
Category B (break for parts): the bodyshell must be crushed, but undamaged parts (engine, gearbox, interior trim) can be stripped and reused in other vehicles. A Cat B car can never legally return to the road.
If you're offered a "bargain" car that turns out to be Cat A or Cat B, walk away, it cannot legally be registered for road use again.
Before October 2017, UK insurers used Cat C and Cat D instead of Cat S and Cat N. You'll still see these categories on older cars' histories, a car written off before the rules changed keeps its original marker, so it's worth knowing what they mean.
A Category C car was repairable, but the repair costs exceeded the vehicle's value, so the insurer wrote it off. The old system was based purely on repair cost versus value; the new system is based on the type of damage. Cat C broadly maps to today's Cat S, repairable structural damage. A Cat C car could be repaired and returned to the road, and many were.
A Category D car had lighter, non-structural damage, but the insurer still chose to write it off, often because repair costs plus admin (hire cars, delays, parts) made repair uneconomical. Cat D broadly maps to today's Cat N. Cat D cars were generally the least severely damaged write-offs, and used Cat D cars often represent the smallest price discount of the write-off categories.
Written-off cars can be genuine bargains, typically 20 to 40% cheaper than an equivalent clean car, but only if you know exactly what you're buying:
If your car has been written off, the insurer will offer you its pre-accident market value, what the car was worth immediately before the damage, not what you paid for it. You don't have to accept the first offer:
Knowing your car's true market value, and its full history, puts you in a far stronger position, whether you're negotiating a settlement or deciding if a buy-back is worth it.
You can legally sell a repaired Cat S or Cat N car, but you must tell the buyer it's a recorded write-off, hiding it is misrepresentation. To get the best price:
Yes, repaired Cat S and Cat N (and older Cat C and Cat D) cars can be insured, but:
The best way to find out what cover will cost is simply to compare quotes. When you do, have the write-off category (Cat S, Cat N, Cat C or Cat D), the repair details and any engineer's report to hand, declaring everything upfront means your policy is valid and your quotes are accurate. Comparing several insurers matters even more for previously damaged cars, because prices vary far more widely than for a clean car.
Yes, once properly repaired. Cat S cars need professional structural repair; Cat N cars need any safety-related components (steering, brakes, electrics) put right. If in doubt, get an independent inspection.
No. Once recorded, the category stays on the vehicle's history permanently and will show on any history check.
Cat C (pre-2017) was defined by repair cost exceeding the car's value; Cat S (current) is defined by structural damage. They broadly cover the same kinds of cars, but the new system tells you more about the damage itself.
Yes, the insurer or owner must notify the DVLA of a Cat S write-off, and the V5C is updated. For Cat N there's no DVLA notification requirement, but the marker still appears on history checks.