BMW April 2022

Regular readers of Automotive Refinisher will be familiar about regular references to ‘Thatcham’ but newer readers may wonder why it crops up so often within AR’s pages…

Many South African drivers are aware that ‘Thatcham’ has something to do with car security matters – but few actually know what it is. Thatcham is the common name for the Motor Insurance Repair Research Centre ( and is named after the Berkshire town in the UK where it is located.

Embracing cars, commercial vehicles and even motorcycles, Thatcham provides stringent testing, along with a standards system for vehicle security products. The above methods of locomotion fall into one of three main categories: Cat 1 products must include a full alarm and immobiliser.

Obviously, an immobiliser stops the car starting by various methods, including interrupting the starter motor, or electronics systems found within a vehicle. Typically, it allows the car to be started only if it recognises an electronic ‘signature’ embedded in the ignition key or transmitted when you open the doors by remote control (key fob). To qualify for Cat 1 status the immobiliser must be ‘passive’: ie, it turns itself on every time you get out of the car.

Cat 2 is an immobiliser only, which must also have ‘passive’ operation. Like any Cat 1 system it must be installed by a professional outfit who should be able to issue a certificate that can be offered to insurers (on some high-performance cars an insurer can refuse offering cover unless at least a Thatcham Cat 2 immobiliser is fitted).

Cat 3 relates to mechanical devices, such as steering wheel locks for cars and commercials, and that all-important disc lock ensuring your motorcycle remains exactly where you left it!

In addition to products that are tested and approved, there is a Q rating for telematic and other high-tech security products such as vehicle trackers. Rather than being an outright test to standards set by Thatcham, the procedure checks that a product does what it says on the tin – and remains suitable for its intended purpose.