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Cat S vs Cat N: UK Write-Off Categories Explained
The six insurance categories used in the UK, what each one means, and how to decide whether to buy a written-off car.
11 min read·Updated May 2026
In one line
Cat A and Cat B should not be on the road. Cat S had structural damage that has been repaired. Cat N had non-structural damage that has been repaired. Cat C and Cat D are the older equivalents of S and N for cars written off before October 2017.
Why write-off categories exist
When an insurer decides a damaged car costs more to repair than it is worth, they pay the owner the market value and the car becomes the insurer's property. The insurer then assigns a category from A to N based on what kind of damage was involved. The category is recorded against the car's registration on the Motor Insurance Anti-Fraud and Theft Register (MIAFTR) and follows the car forever, even after repair.
The UK system was updated in October 2017. Cars written off before then still carry the old letters (A, B, C, D). Newer write-offs use A, B, S, N. The change was driven by rising repair costs (especially for modern aluminium and composite bodies) which meant many lightly damaged cars were being written off purely on cost.
Category A – Scrap only
Damage so severe the entire car must be crushed. Nothing on the vehicle is allowed to be reused, not even unbroken parts. Cat A cars cannot legally return to the road.
Should you buy one? No, and you should not be able to. Walk away from anyone offering you a “repaired Cat A”.
Category B – Break for parts
The body shell must be crushed but undamaged components (engine, gearbox, doors, seats) can be reused in other vehicles. The original Cat B car cannot legally return to the road.
Should you buy one? Same answer as Cat A. If a seller claims their Cat B has been “rebuilt”, the car is not legal to drive.
Category S – Structural damage, repairable
The chassis, subframe or another structural element was damaged. The car can be repaired and put back on the road, but the repair must be done by someone qualified. After repair, an MOT and a DVLA re-registration (sometimes a VIC check) are required.
Should you buy one? Possibly. Expect to pay 20 to 40 per cent less than a clean equivalent. Insurance is harder and more expensive. Get an independent inspection focused on the structural repair.
Category N – Non-structural damage, repairable
Damage was cosmetic or to non-structural parts: lights, panels, electrics, infotainment, airbags. The car's frame is sound. Often the original “write-off” was driven by repair cost exceeding market value, not danger.
Should you buy one? Sometimes a good deal. Expect to pay 10 to 25 per cent less than a clean equivalent. Still inspect carefully and check the repair quality.
Category C – Pre-2017 equivalent of S
For cars written off before October 2017. Indicates repair cost exceeded market value, but the car was repairable. The damage threshold differed slightly from Cat S so treat it as a rough equivalent rather than identical.
Category D – Pre-2017 equivalent of N
Lower repair-cost-to-value threshold than Cat C. Often light damage, sometimes purely cost-based write-offs on older or cheap cars where any repair was uneconomic.
What does buying a Cat S or Cat N actually cost you?
Resale value
A Cat S marker typically knocks 20 to 40 per cent off resale value compared to an undamaged equivalent. Cat N knocks 10 to 25 per cent. The percentage is roughly stable across owners, so if you buy at a 30 per cent discount you will probably sell at a similar discount later.
Insurance
Some insurers will not cover Cat S or Cat N cars at all. Those that do typically charge a 10 to 20 per cent premium uplift. Always get a quote before you commit to the car. Be prepared to use a specialist broker.
Finance
Mainstream finance lenders often refuse to lend against written-off cars. If you need finance, factor this in before you fall in love with the car. Cash buyers face no such obstacle.
Safety
This is the part that should drive your decision. Cat N is usually safe if the repair was competent. Cat S can be safe but requires care: structural repairs done badly can fail in a future crash. Always commission an independent inspection from someone qualified in body and chassis repair.
How to check if a car is a write-off
Run a paid vehicle history check. Every UK paid HPI-equivalent check queries MIAFTR and returns the category if one exists. This is the only reliable source.
Ask the seller directly. Dealers are legally required to disclose write-off status under consumer law. Private sellers commit fraud if they hide it. Get the answer in writing.
Check the V5C. If the V5C mentions a DVLA inspection (formerly a VIC check), the car has been involved in a serious incident.
Inspect for repair signs. Mismatched paint, panel gaps that are not parallel, overspray on rubber seals, fresh underseal, and new bolts on structural components are all clues.
The exceptions: when a Cat S or Cat N makes sense
You plan to keep it long-term. The resale hit hurts most if you sell within three years. Owners keeping the car ten years recoup most of the discount as use.
The discount is real. Some sellers price a Cat S or N at 5 to 10 per cent below market. That is not a deal. You need at least 20 per cent on Cat S, 15 per cent on Cat N.
The repair documentation exists. A proper bodyshop invoice with VAT, parts list, and repair photos makes Cat S far safer to buy. A vague “mate fixed it” story does not.
Confirm before you buy
Our free check covers DVLA basics. Run a full Vehicle History Check to confirm the car is not in the MIAFTR write-off register.
No. Once MIAFTR has the marker, it stays on the car's record permanently. Anyone offering to “clear” a write-off is committing fraud.
Do I need to tell my insurer if I buy a Cat S or N?
Yes. It is a material fact. Failure to disclose voids your policy and any future claim.
Will a Cat S pass an MOT?
Yes, if repaired properly. The MOT does not assess write-off history, only current roadworthiness. A car can be a clean MOT and still be a Cat S.
What about “unrecorded” damage?
If the owner paid for repairs out of pocket without an insurance claim, there is no MIAFTR record at all. A history check will not flag it. This is where a good pre-purchase inspection earns its money.
The bottom line
A, B: hard no. S, N, C, D: maybe, with the right discount, the right insurance quote, and the right inspection. Always run a paid history check first so you know exactly what you are negotiating against.
