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Guide

Cat S, Cat N and Write-Off Categories Explained

Updated July 2026

You’ve found a car that looks like a bargain — a few thousand pounds under the going rate. Then you spot two letters in the advert: “Cat N.” Is that a deal-breaker, or a smart buy? A written-off car isn’t automatically a scrap heap — but you need to understand exactly what the category means before you hand over any money.

Why this matters

An insurance write-off is a car the insurer decided wasn’t economical to repair after a claim — often because the repair cost was high relative to the car’s value, not because the damage was catastrophic. Many written-off cars are repaired and returned to the road perfectly safely. Others hide serious structural damage behind a shiny respray.

Crucially, a write-off record does not appear in the free gov.uk MOT history. A repaired write-off can hold a valid MOT and look flawless. The only way to know is a vehicle history check that includes insurance data.

The four write-off categories

  • Category A (Scrap) — so badly damaged it must be crushed. Nothing may be salvaged, not even parts. It can never legally return to the road.
  • Category B (Break) — the body shell must be destroyed, but some serviceable parts may be reused. The car itself must never return to the road.
  • Category S (Structural) — structural damage (chassis, frame, crumple zones) that has been, or can be, repaired. Legal to drive once properly repaired.
  • Category N (Non-structural) — damage that isn’t structural — panels, lights, electrics or cosmetic. Legal to drive after repair.

If you ever see a Category A or B car advertised as roadworthy, walk away and report it — those cars must never be driven.

Should you buy a Cat S or Cat N car?

It can be a genuine bargain — but only with your eyes open. Before buying a repaired write-off:

  • Ask for repair evidence — photos of the original damage, receipts, and who carried out the work. No paperwork is a red flag.
  • Get an independent inspection — a repaired Cat S car especially should be checked by a qualified engineer.
  • Budget for lower resale value — a write-off record follows the car forever and reduces what you’ll get when you sell.
  • Check insurance first — some insurers charge more, or decline the car entirely. Get a quote before you commit.

⚑ Red flags checklist

  • The seller doesn’t mention the write-off at all (check it yourself before viewing)
  • No repair receipts or evidence of who did the work
  • A Cat S car with no independent inspection offered
  • Panel gaps, mismatched paint, or overspray on rubber seals and trim
  • A price that’s “too good” with no clear explanation

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Frequently asked questions

Is it safe to buy a Category S or Category N car?+
It can be, if the repair was done properly and documented. Category S means structural damage was repaired; Category N means non-structural damage. Both are legal to drive and sell once repaired, but you should insist on repair evidence and, for a Cat S car especially, an independent inspection.
What is the difference between Cat S and Cat N?+
Cat S (Structural) means the damage affected the car’s structure — the chassis, frame or crumple zones — and was repaired. Cat N (Non-structural) means the damage was cosmetic or to parts like panels, lights or electrics. Cat S is generally the more serious of the two.
Does a write-off show up on the free MOT check?+
No. Insurance write-off records aren’t part of the MOT data, so a repaired write-off can hold a valid MOT and look perfect. You need a check that includes insurance write-off data — that’s part of the AI Plate Checker full history report.
Can a Cat A or Cat B car be driven?+
No. Category A cars must be crushed entirely and Category B cars must have their body shell destroyed — neither may ever return to the road. If one is advertised as roadworthy, walk away and report it.