What does it mean when car security is Thatcham approved?


We take fairly robust car security for granted these days and much of that is down to Thatcham Research. It is an organisation that tests and rates car security devices. The aim is to give car buyers an idea which of the vast array of security equipment is any good.

What is Thatcham-approved?

Every year Thatcham Research assesses new car alarms, immobilisers and security devices such as locking wheel nuts and tracking systems. It then gives the devices a security certification after assessing their features and functions. This certification or approval falls into a series of different categories. The lower the category number, the more protection a device should provide.

Thatcham Category 1

This is for combined alarm and immobiliser systems. The alarm must sound if someone breaks into the car, tilts or tows it away. And the immobiliser must set itself. That means the driver doesn’t have to do anything to stop the car being started without the key.


Thatcham Category 2

This is for electronic immobilisers only. It must isolate the vehicle control unit in order to prevent the car running normally. As with Category 1, the immobiliser must set itself and must resist third party devices grabbing its codes.

Category 2/1

If a car has a Category 2 immobiliser and the manufacturer or owner fits a Category 1 alarm retrospectively, it falls into this class.

Category 3

This is a class for physical immobilisers. These prevent the cars being driven until they’re removed and is for what’s known as aftermarket kit. This is equipment such as steering or gear lever locks that you buy to fit to the car.

Category 4

These are the wheel nuts that prevent people nicking car wheels.

Category S5

This is for devices that track stolen cars. They can also shut down stolen cars remotely. This stops thieves driving them any further.

Category S7

These devices locate stolen vehicles. But unlike Category S5, S7 rated devices can’t shut down cars remotely.

Does your car have Thatcham-approved kit?

It probably does, yes. And the newer and more expensive the car is, the more likely it is to have Thatcham kit. However, your car’s user manual will tell you whether it does or not.

What is Thatcham Research?

It’s an organisation that gets its name from the Berkshire town that it’s located in. Set up in 1969 it was officially known as the motor insurers’ automotive research centre, Thatcham Research, or simply Thatcham for short.

Its aim is to reduce the cost of motor insurance claims while maintaining safety standards at the same time. It is Thatcham that sets the insurance group ratings. These help to guide how much our motor insurance premiums cost.

The organisation provides the motor industry with repair data too. This helps formulate repair techniques that enable damaged cars to be returned to their pre-crash state safely, cost effectively and efficiently.

Thatcham also works with Euro NCAP, crash testing cars and giving an independent assessment of how safe they are in real-world crash conditions.

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