A "Cat S" car is one an insurer has written off after suffering structural damage — but which can be legally repaired and returned to the road. Buy one wisely and you could save thousands; buy one carelessly and you could inherit a badly repaired, unsafe car. Here's what you need to know.
What "written off" actually means
An insurer writes a car off when repairing it costs more than the car is worth, or when the damage makes it unsafe. It doesn't always mean the car is wrecked — sometimes an older but valuable car is written off over relatively minor damage simply because the repair bill exceeds its market value. The insurer then assigns a category.
The write-off categories
- Cat A — Scrap only. The whole vehicle must be crushed. Never legal to drive again.
- Cat B — Break for parts. The body shell is crushed, but some parts can be reused. The car itself can't return to the road.
- Cat S — Structural damage. Damage to the chassis or a structural part. Repairable and legal to drive once fixed and re-registered.
- Cat N — Non-structural damage. Cosmetic or electrical damage only. Legal to drive once repaired.
Cat S and Cat N replaced the older Cat C and Cat D in October 2017, so older records may still show C or D.
Is it safe to buy a Cat S car?
It can be — Cat S cars typically sell for 20–40% less than an equivalent clean car, which is a genuine saving. But structural damage means the car's frame was affected, so the quality of the repair is everything. Before buying a Cat S car:
- Get an independent inspection from a qualified mechanic or engineer.
- Ask for documented proof of the repairs and who carried them out.
- Check the price genuinely reflects the history — and factor in lower resale value later.
- Tell your insurer: some charge more, or won't cover certain write-offs.
Never buy a Cat A or Cat B car to drive — it's illegal and dangerous. If a seller offers one "cheap, ready to go", walk away.
How to check a car's write-off status
You can't tell a repaired write-off by looking at it — that's the whole problem. Run a write-off check on the registration and GuruCarCheck reveals any insurance total-loss record and its category as part of a full report from £7.99. It's the only reliable way to know before you view the car.
The bottom line
A Cat S or Cat N car isn't automatically a bad buy — plenty are repaired to a high standard and represent good value. The danger is buying one without knowing, or at a price that doesn't reflect the history. Always check the category first, then inspect thoroughly.