Category S — Structural damage
Cat S means the vehicle's structural integrity was compromised. Chassis, A-pillar, B-pillar, subframe, suspension mounting points. The car was deemed uneconomical to repair by the original insurer but is structurally repairable.
Real-world examples: bent chassis from a moderate impact, damaged front subframe, rear-end collision with structural intrusion.
Effect on value: 20-30% discount vs equivalent unrecorded car.
Insurance: Most major insurers cover Cat S but premiums are 15-25% higher.
MOT and roadworthiness: Cat S cars must pass a VIC (Vehicle Identity Check) before re-registration. Once on the road, they're legally identical to any other car.
Category N — Non-structural damage
Cat N means the damage was uneconomical to repair but didn't affect the car's structure. Cosmetic, electrical, or non-essential mechanical damage.
Real-world examples: hail damage, water damage to interior trim, broken windscreen + replacement parts cost > car value, theft recovery with stolen items not replaced.
Effect on value: 10-20% discount.
Insurance: Easier to insure than Cat S. Premium increase typically 5-10%.
MOT and roadworthiness: No VIC required. Re-registered and good to drive once repaired.
Which one is worth buying?
Cat N with documented repair and 10-15% discount — often worth it. Stack the savings against a 5% lower future resale.
Cat S with documented repair, 25-30% discount, and an independent engineer's inspection — can be excellent value if you'll keep the car 5+ years. Skip if you plan to PX in 18 months.
Either category without paperwork showing the repair was done properly — walk away. The mechanic who did it may have cut corners.
Either category if the discount is less than 10% — walk away. There's no benefit.
What to check on a write-off car
Get the original insurer's damage report — most won't have it, but some good sellers do.
Pre-purchase inspection by an independent engineer — £200-£300. Mandatory for any Cat S car.
Paint depth gauge across all panels — should be roughly consistent. Big variation = repaired bodywork.
Inspect under the bonnet and underneath — straight edges, no overspray, no welding marks on the chassis.
HPI check — confirm the category and check for any other markers.
See our full pre-purchase inspection guide.
Reselling a write-off car
Always disclose the category. Required by law and by basic decency.
Expect 20-30% (Cat S) or 10-15% (Cat N) below market value when selling. Plan for this when negotiating purchase.
Dealers often won't part-exchange write-off cars — you'll need to sell privately.
Provide all repair documentation — receipts, engineer's reports, insurer's documents. Buyers pay more for documented repairs.