Cat S and Cat N write-offs, explained

A "write-off" does not always mean a wrecked car — it means an insurer decided repair was not economical. Two of the four categories can legally return to the road, and they sell at a discount that can be a bargain or a trap.

The four categories

• Cat A — scrap. The whole car must be crushed; even parts cannot be salvaged.
• Cat B — break for parts. The body shell must be destroyed; parts may be sold.
• Cat S — structural damage, repairable. Chassis or crash-structure damage that has been (or must be) professionally repaired before returning to the road.
• Cat N — non-structural damage, repairable. Cosmetic panels, electrics, interior — the structure was untouched.

Before 2017 the repairable categories were called Cat C and Cat D — you will still see those on older cars.

What a marker does to the car

A recorded write-off typically knocks 20–40% off the value permanently, follows the car through every future sale, can raise insurance premiums, and some insurers or finance companies decline them altogether. None of that is visible on the driveway: the register that holds these markers (MIAFTR, maintained by the insurance industry) is separate from MOT and tax records.

Buying one sensibly

1. Confirm the category and loss date with a write-off check.
2. Ask for repair invoices and photos — a proper Cat S repair has a paper trail.
3. For Cat S, consider a post-repair inspection by an independent engineer.
4. Pay a written-off price, not a clean-history price.