What is a Cat S car?

If you look through many used car adverts, you might come across ‘Category S’ cars, but what are these and should you be wary?

By David Ross November 20, 2023

Cars that have previously been written off by insurers are often massively tempting as they can be as much as 35% cheaper than equivalent examples on the market. A Cat S car will be substantially less expensive than one that hasn’t been written off.

In 2017, the Association of British Insurers changed the names of insurance write-offs to Category S and Category N – but what do they mean and what is a Cat S car?

First, we need to consider the classifications. If a car that has been damaged in a crash, flood, or a fire and is too expensive to repair – being expected to cost more to repair than it is worth at the time – it may be written off by the insurer. There are four categories of write-off: A, B, S and N. These replaced the old system that included Category C and Category D.

A Category S (or Cat S) car is one that has suffered structural damage, but is still deemed to be repairable, albeit at greater expense than its market value. If it is repaired, then the car’s salvage category is recorded on the V5 and remains with the vehicle for life, which reduces its appeal for many drivers and makes it worth less when it comes to sell it on.

However, it also means there are some huge bargains about, and many skilled repairers will buy Category S cars from salvage auctions and fix them up. The key is understanding the condition of the car and the quality of repairs.

It’s difficult to know if a written-off Category S car has been properly repaired and is safe to drive, without a full mechanical inspection. As such, you ought to factor an inspection into the cost of purchase. You should consider, too, that a write-off is based on the value of a car versus the cost of repair – a car written off at 10 years old is likely to have sustained far less damage than one written-off at two years old, for example. 

Beyond safety, dealing with Category S cars is risky in other ways. The Cat S categorisation can affect the cost of insurance and is likely to reduce the amount you can sell the car for in future, or claim for should it be damaged again. It can even reduce your chances of selling the car at all, as many buyers will choose to avoid buying a Cat S car.

This is why BuyaCar does not sell cars that have been written off – whichever category they fall into – and we recommend caution to ensure that no car you’re looking to buy is registered as a Category S vehicle, unless you’re fully aware of the car’s condition and its value once the fact it’s a write-off has been factored in.

How do Cat S and Cat N differ?

The S and N categories replaced C and D as a measure of the severity of damage. Category A is the worst category of write-off and means the car must be scrapped in its entirety. Category B cars cannot be put back on the road, but can be stripped for spare parts. 

The former means the car has acquired fundamental damage to a key part of the vehicle’s structure and while it is deemed suitable for repair, it must be repaired properly. Category N cars are a lower risk, as they are not considered structurally damaged. Usually that means dents or scrapes that can’t be repaired within the car’s market value. As a result, Cat N cars are often older. 

Why do insurers write off Cat S cars?

Structural damage can often be expensive to repair and insurers have to balance the cost of making repairs versus the cost of a full pay-out. Within that assessment they include the cost of administration, plus the cost of hire or courtesy vehicles for the claimant. 

If the cost of making repairs and covering the subsequent related bills exceeds the value of the car, they’ll pay the policyholder a settlement figure and write off the car. There’s no hard and fast rule, but once the repair costs start to pass 50% of the car’s overall value, then the insurer may well write it off because of the additional expenses.

Who repairs Cat S cars?

Most Cat S cars are sold via salvage auctions and are bought by independent garages and body shops with the specialist equipment required to repair Category S cars. Because the cars cannot be sold for the same prices as those not recorded as write-offs, they can buy them for a lower price than undamaged cars.

Many garages that repair write-offs are reputable garages but the fact that their work does not, by law, have to be independently inspected, means consumers cannot be entirely confident a repaired Category S car is safe for the road. If you do wish to buy one, you should purchase from a registered repairer with the VBRA, which is the Vehicle Body Repair Association.

How can I know a Cat S car is safe?

As there are no strict controls on repair, then there is no guarantee. The best advice is to get it independently inspected and at the very least, put it through an MoT test at a garage independent from the dealer selling it.

The majority of issues that would make the car unsafe to drive would be identified during an MoT, so you’d hope that anything untoward would be flagged in that.

Could I buy a Cat S car without realising?

The law is very strict on regulations for selling a Cat S car. Important information about its status cannot be concealed from you by a dealer – and that’s the law. Check the paperwork thoroughly and if you have any suspicions, check its history with a vehicle information company such as HPI

Also ask to inspect the car’s V5C registration document when buying, as information about its write-off status must be recorded on the document by law.

You’re at greater risk when buying privately. To be on the safe side, run an HPI check or similar on the car and this should alert you to any cars that have been registered as write-offs.

We run HPI checks on every car we stock at BuyaCar. Learn more about how BuyaCar works here.

Will I have to pay more to insure a Cat S car?

Generally speaking, yes. Insurers base their quotes on risk and a Category S car presents a higher risk than cars that are guaranteed to be structurally sound. Their previous and present conditions are uncertain, and the car’s market value is unclear if it’s written off a second time.

Other categories

Category A: Car may not be repaired, and must be crushed.
Category B: Car may have its usable parts recycled, but it also must be crushed.
Category N: A write-off that has not sustained any damage to its structure, which may be repaired and safely returned to the road.

What is a car’s structure?

The car’s structure is defined by the Association of British Insurers (ABI), one of the organisations behind the salvage code. It also defines the term ‘damage’ as any structural part requiring realignment to its original dimensions or replacement. A car’s structure comprises the front bulkhead, front and side chassis rails, rear cross members, inner wings, wing supports, A and B-pillars and sills. Critically, suspension arms and steering components are not classed as structural so it’s imperative that these are properly inspected.