UK insurance write-off categories explained

If you're buying a used car in the UK and the HPI report flags it as a previous insurance write-off, the next question is which category. The answer determines whether the car is even legal on the road, what it should cost, and what your insurer needs to know.

The current four-category system has been in force since 1 October 2017 and replaces the older A/B/C/D classification. Both still appear on UK car histories — older write-offs keep their original category for life.

The four current categories

Cat A — scrap only

The entire vehicle must be destroyed. This includes the body shell and every part, including the engine, gearbox and components that might otherwise be salvageable. Cat A is reserved for the most severely damaged vehicles — typically write-offs from major fires or catastrophic structural damage.

Cat A cars cannot legally return to the road. If you see a Cat A car for sale, it has been illegally re-registered or the seller is misrepresenting the category. Walk away and report.

Cat B — break for parts

The body shell must be destroyed, but parts may be salvaged for sale or use on other vehicles. Like Cat A, the original vehicle cannot return to the road under any circumstances.

A Cat B car for sale is illegal. The parts can legally be sold separately, but the registration is permanently extinguished.

Cat S — structurally damaged, repairable

Cat S means the car has structural damage — to the chassis, crumple zones, suspension mounts or other safety-critical structural components — but the damage is repairable to a roadworthy standard.

Cat S cars can return to the road after professional repair. They keep the Cat S marker on the V5C and on every HPI check thereafter, and they must be declared on insurance.

Cat N — non-structural damage, repairable

Cat N covers everything that isn't structural — cosmetic body panels, lights, minor electrical components, interior damage. Many Cat N write-offs are economic rather than mechanical: the cost of cosmetic repair simply exceeded the insurer's threshold for the car's age and value.

Cat N cars can return to the road with appropriate repair, but again the marker stays on the history forever.

What each category does to price

| Category | Can return to road? | Typical price effect | |----------|---------------------|----------------------| | Cat A | No (scrap only) | n/a — illegal to sell as a vehicle | | Cat B | No (parts salvage) | n/a — illegal to sell as a vehicle | | Cat S | Yes, after repair | 30–40% below clean equivalent | | Cat N | Yes, after repair | 20–30% below clean equivalent |

The exact discount depends on age, repair quality and the originating damage. A 12-year-old Cat N car with cosmetic-only damage and a documented repair sells closer to the lower end (20%); a 4-year-old Cat S car with major structural repair work sells nearer the upper end (40%).

Insurance and write-off cars

Insurers will typically cover Cat S and Cat N cars, but:

• You must declare the category at the point of buying or renewing cover. Failing to disclose voids your policy.
• Premiums are usually higher — typically 5–20% over an equivalent clean car.
• Some insurers refuse cover entirely for write-offs over a certain age. Specialist write-off insurers cover the gap.
• Future write-off thresholds drop: a Cat N car damaged again is more likely to be written off the second time because its base value is lower.

How to buy a Cat S or Cat N car safely

1. 1

   Get the original write-off paperwork

   Insurer's write-off engineer's report, photographs, repair invoices, MOT pass after repair. A car with no documentation is much higher risk.
2. 2

   Inspect for repair quality

   Mismatched paint, uneven panel gaps, overspray on rubber seals, indicator-housing tabs broken on installation. Cat S cars warrant a professional inspection — AA, RAC or specialist body shop.
3. 3

   Verify chassis numbers and VINs

   A repaired Cat S car should still have its original VIN stamped intact. A re-stamp is a legal repair only with the appropriate paperwork.
4. 4

   Confirm the post-repair MOT

   Cat S cars should have an MOT after the repair. The MOT trail will show the test that re-introduced the car to the road.
5. 5

   Discount the price appropriately

   Don't pay clean-example money for a Cat S or Cat N car. Use a paid valuation, then deduct 20–40%.
6. 6

   Tell your insurer

   Get a written quote based on the actual category before you commit. Some insurers refuse quotes only after you've bought.

Re-cat'd and structural-damage write-offs

Some Cat N cars are later upgraded to Cat S after subsequent damage assessments. The newer category supersedes the older one, but the history shows both.

A car with multiple write-off entries — even minor — is a far higher resale risk than one with a single entry. The market knows this and prices accordingly.

Frequently asked questions

The Q&A repeated below covers the most common write-off questions. The short version: Cat A and Cat B cars are off the road permanently; Cat S and Cat N can return after proper repair, with discount pricing and insurance disclosure required. The HPI report tells you which applies.