What do the car insurance write-off categories mean?
When repair is uneconomic or unsafe, an insurer declares the vehicle a total loss and assigns a category. The UK system was revised in 2017 to classify by damage severity rather than by repair cost, which is why older guides describing categories C and D are out of date.
The current categories:
Category A — scrap. The entire vehicle must be crushed. Nothing may be salvaged, not even parts. Reserved for the most severe damage, including some fire and flood losses.
Category B — break for parts. The body shell must be crushed, but serviceable components may be removed and reused. The vehicle can never legally return to the road.
Category S — structural damage. The vehicle sustained damage to its structural frame or chassis. It can be repaired and returned to the road, but the repair must be done properly, and the structural history stays with the car permanently.
Category N — non-structural damage. No structural damage; the write-off was economic, or involved non-structural safety components. This can include electrical faults, airbag deployment, or cosmetic damage on a low-value car. It can be repaired and returned to the road.
What this means practically:
Buying a Cat S or Cat N car is legal and can be good value, but the marker is permanent, resale is harder, some insurers will not cover it, and quality of repair varies enormously. An independent inspection is essential, and a full history check will reveal the marker even when a seller does not.
If your own car is written off, the insurer pays market value and normally takes ownership. You can usually buy back a Cat S or N vehicle at salvage value if you want to repair it yourself.
Category markers must be disclosed when selling.