Car insurance discount for immobiliser — how much can you really save?

Insurance pricing is risk-based. An insurer that can demonstrate a vehicle is significantly harder to steal charges less to cover it, because the probability of paying a theft claim is lower. Aftermarket relay immobilisers — particularly those that operate independently of the factory keyless entry system — represent a measurable, documentable reduction in theft risk. LockCar’s products are specifically designed to provide the physical relay break that insurers recognise as the most effective category of aftermarket theft protection.

Why UK insurers discount for immobilisers

The UK insurance market prices vehicle theft risk based on make, model, postcode, parking location, and security specification. Every element that reduces theft probability reduces the expected claims cost and therefore the premium. Factory immobilisers are already priced into the base premium for each vehicle. Aftermarket immobilisers — particularly those that operate outside the factory keyless entry vulnerability — represent an additional risk reduction that is not already reflected in the base rate.

UK insurers that have developed specific aftermarket security policies typically distinguish between immobilisers that supplement the factory system (which they rate as medium additional protection) and immobilisers that operate independently of the OEM system entirely (which they rate as high additional protection). LockCar’s hardwired relay break, which operates independently of the key fob signal and the OBD system, falls in the latter category for insurers that understand the technical distinction.

The trend towards insurer-mandated aftermarket security is accelerating. Several UK specialist insurers — particularly those covering Land Rover, BMW, and Toyota models in high-theft postcodes — have moved from offering discounts to requiring evidence of aftermarket immobiliser fitment as a condition of cover. LockCar provides all documentation required to satisfy these conditions.

How much can you save on car insurance?

Insurance discounts for aftermarket immobilisers vary by insurer, vehicle model, postcode, and the specific product fitted. Headline discounts advertised by specialist insurers typically range from 5% to 25% on the theft and TPFT (third party, fire, and theft) component of the premium. For high-value vehicles in high-theft postcodes — the scenario where relay attack risk is highest — discounts at the upper end of this range are achievable.

The practical saving depends heavily on the base premium. A £600 per year comprehensive policy with a 15% discount generates £90 per year in premium savings. Against a LockCar installation cost of £150 to £259, the payback period is less than two years — after which the security benefit and insurance savings continue indefinitely. For higher-value vehicles with premiums above £1,000, the saving can exceed the installation cost within the first year.

Some insurers go further. For Land Rover, Range Rover, BMW X5, and Toyota Land Cruiser models in West Midlands, Greater Manchester, and South Yorkshire postcodes, certain specialist insurers have removed some models from standard cover entirely unless aftermarket security is fitted. In these cases, LockCar installation is not just a discount driver — it is a prerequisite for obtaining cover at all.

What your insurer requires

When applying for an insurance discount for an aftermarket immobiliser, most UK insurers will ask for the product name and manufacturer, a description of how the product works (particularly whether it is independent of the factory keyless system), and proof of professional installation. Some insurers reference Thatcham Research categories — immobilisers are generally Thatcham Category 2 or equivalent — and may ask for a Thatcham rating certificate or equivalent documentation.

LockCar provides a full installation certificate including device serial number, installation date, vehicle registration, and a technical description of the relay break mechanism and authentication method. This documentation is accepted by the majority of UK insurers and can be submitted at the point of policy application or renewal. Contact us after installation if your insurer has specific documentation requirements.

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