Car security systems and the price of your insurance

April 7, 2022

Making sure your motorcar is as secure, safe and traceable as possible by having an insurer-approved car alarm, immobiliser or GPS tracker fitted can help reduce the cost of your car insurance premiums.

However, not all main UK auto insurers will offer you anti-theft discounts. For example, LV doesn’t offer a discount for vehicles installed with an alarm, immobiliser or tracker.

So if you own a super secure motorcar that has an insurer approved alarm, immobiliser or tracker (or all 3) installed, you should shop around and compare quotes from a variety of insurers to find the best deals with the biggest discounts.

But what are ‘insurer approved’ car security systems and how do you find out if they’re already installed in your vehicle?

Here’s all you need to know about car insurance discounts for security systems and the best types of anti-theft devices in the UK.

In this guide:

What car security systems lower car insurance?

What car alarm can lower insurance?

What car immobiliser can lower insurance?

What is an insurance approved vehicle tracker?

What car locking device can lower insurance?


Does my car have a Thatcham alarm or immobiliser?

What is an aftermarket immobiliser?

Car thief looking through window

What car security systems lower car insurance?

As highlighted above, the three main car security features that can bring about the biggest discounts with most mainstream motor insurers are:

  • alarms
  • immobilisers
  • tracking systems

However, there are additional security devices certain insurers may offer additional discounted premiums for such as using a dashcam, and some smaller, cheaper but effective anti-theft security devices and measures that can help lower insurance costs too. 

Here’s a comprehensive list of car security measures and devices that may either help reduce your insurance costs or can help prevent your vehicle from being stolen (which could mean losing your no claims bonus and increased premiums as a result).


Motor alarms can be a great deterrent for thieves but they’re not foolproof as of course (and we’re all guilty of it) most of us assume a car alarm has gone off by accident and completely ignore it!

However, if it’s in the middle of the night as opposed to a busy supermarket car park, most of us will pop our head out of the window to see where the [hell] that noise is coming from.

Not all car alarms are noisy. Certain cars have ‘silent arms’ installed that will sneakily only notify you that your car is being broken into but not the thief, so you can contact the police and report the incident immediately. (And don’t be tempted to be a ‘have a go hero’ if you have a silent alarm and this happens; reduced car insurance premiums are not THAT important!)

What car alarm can lower insurance?

Category 1 Thatcham car alarm insurance discounts are pretty much guaranteed with most insurers as you have the ultimate in car security by having both a Thatcham approved (and therefore an insurer-approved) alarm and immobiliser in one.

You might like: Are car alarms worth it?

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When you apply for insurance quotes, auto insurers will want to know if your vehicle has a ‘factory-fitted immobiliser’.

This is because an immobiliser is the number one defence against auto theft as your car can only be stolen by using your car keys; it can’t be ‘hotwired’ (although keyless car theft is an active issue - more on this below).

What car immobiliser can lower insurance?

Either a Thatcham Category 1 (alarm and immobiliser in one) or a Thatcham Category 2 electronic immobiliser will help reduce your premiums with most auto insurers.

Note: If your car currently only has a Thatcham Category 2 immobiliser, you can pay to upgrade your car’s security system to Category 1 by having a Thatcham Category 2.1 upgrade.

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Car security system GPS tracking will not only prevent your car from being stolen but it can most certainly help you get your vehicle returned and, if you get your car back undamaged, negates having to make a claim on your car insurance.

What is an insurance approved vehicle tracker?

  • A Thatcham approved Class S5 post-theft tracking device is the tracker most favoured by insurers as this not only traces your car’s location but is also capable of immobilising your vehicle remotely.
  • A Thatcham Class S7 tracker is less sophisticated than a Class S5 tracker as you cannot remotely disable a car but you can still track it.

If you use a top-notch Thatcham Class S5 approved tracker and subscribe to the requisite asset location system, Rewire Security says that you can save up to a whopping 20% on your car insurance premiums!

Did you know that black box car insurance devices (also known as telematics or pay as you go car insurance) give you the ability to track a stolen car and some devices also have the ability to immobilise a car remotely? This means if you take out black box car insurance, not only can you reduce your premiums by driving safely, you can have a great anti-theft tracking device at your disposal for free.

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Dash Cams

As all the main auto insurers now accept dashcam footage in the event of a car accident claim being made, there are certain insurers who will offer up to a 20% discount if you use one!

As a dashcam isn’t particularly a security or safety measure, you will not find a Thatcham approved dashcam on the market (although no doubt some unscrupulous sellers will say their product is ‘Thatcham approved’). However, you will find many insurer-approved dash cams at reasonable prices that can slash your insurance premiums.

So before buying a dashcam, it’s worthwhile doing your research and checking with your insurer about what brands and makes of dashcam can lower your premiums.

Search Dash Cams

Read: The best dash cams

Smart key protection (Anti RFID theft wallet)

Keyless car theft is on the rise: many of the UK’s 89,000 cars stolen during 2020 were as a result of keyless theft.

Keyless car theft is where thieves clone a car key fob’s technology to steal a vehicle. However, in order to do so, they need a signal from your key fob.

Storing your keys in an RFID-blocking wallet (more commonly known as a ‘Faraday Pouch’) can prevent this from happening. Costing approximately £10, a signal-blocking pouch is a cheap but effective security measure for any keyless vehicle.

Buy a Faraday Pouch

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Security window etching

According to Halfords, vehicles with etched windows are 45% less likely to be stolen and your chances of recovering a stolen vehicle with etching are improved by 50%.

A logo of the International Security Register (ISR) together with a unique code can be etched onto your window and this information is stored on a secure database that can be accessed by the police 24/7. This security measure is as cheap as chips at around £20.

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Steering wheel locks, wheel clamps and handbrake locks

Whilst they can be a little tedious and fiddly to use, a steering wheel, handbrake or wheel lock and clamps can prevent theft and reduce insurance costs.

What car locking device can lower insurance?

A Thatcham Category 3 mechanical immobiliser such as a steering wheel lock, wheel clamp or motorbike chain.

In addition, if you have alloy wheels, you should already have Thatcham approved Class 4 wheel-locking nuts to protect them from being stolen.

Note: You must use whatever security locking device you declare to your insurer every time you need to secure your vehicle otherwise you could invalidate your policy and have a claim refused.

Buy a Steering Lock

Read more: Car security: the best anti-theft locking devices

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Driveway cameras and security lights

As mentioned above, parking your car on a driveway rather than a public road helps reduce premiums and making sure a CCTV camera and bright security lights are focused on your car can help too.

You might like: Why has my car insurance increased?


Does my car have a Thatcham alarm or immobiliser?

To find out if your vehicle has a Thatcham approved [factory-installed] alarm or immobiliser, you can:

  • check your owner’s manual / vehicle’s handbook - if this is lost, you can usually download a copy for free from a car manufacturer’s website or view a copy for free elsewhere on the internet
  • contact your car’s manufacturer to ask
  • ask a qualified mechanic to check - perhaps ask the next time you have an MOT or service

Note: If your vehicle was manufactured prior to 1998 when immobilisers were first made mandatory, your motor will not usually have a car immobiliser installed, Thatcham or otherwise.

To specifically find out more about immobilisers and view a full list of Thatcham approved security systems and devices read: How to find out if your car has a factory-fitted immobiliser

Does my car have an Immobiliser?

What is an aftermarket immobiliser?

If your motorcar doesn’t have a factory-fitted immobiliser installed, you can optionally pay for an ‘aftermarket immobiliser’ installation.

If an aftermarket immobiliser, alarm or tracker isn’t approved by Thatcham, then they are referred to as being ‘Q Class systems - non-categorised aftermarket systems’. Whilst Q Class systems are generally cheaper to buy, they will not usually reduce your car insurance premiums anywhere near as much as the highly accredited Thatcham approved and rated systems or devices.

For a full list of approved Thatcham device suppliers, you can search for any products including an immobiliser using the Thatcham Security Certification search tool on Thatcham Research’s website.

Note: Thatcham Security Certification does not guarantee insurer approval as this is negotiated separately on an individual basis by the product manufacturer and their insurance company partner/s. So you should specifically check with your own insurer what type of Thatcham alarms, immobilisers or trackers will help to reduce the cost of your insurance premiums the most.

In addition to the above security measures, there are other ways in which you can lower the cost of your car insurance. To find out more, read: 10 tips and tricks for lowering the cost of your car insurance.

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