Relay Theft Explained: How Keyless Cars Are Really Stolen
Relay Theft Explained: How Keyless Cars Are Really Stolen
If your car has keyless entry, the biggest threat to it probably isn't a smashed window — it's relay theft, and it can take under a minute, without your key ever leaving the house.
How It Actually Works
Keyless entry systems work by constantly listening for a signal from your key fob at short range, so the car unlocks and starts without you pressing a button. Relay theft exploits exactly that convenience: one device is held near your front door (or wherever your keys sit) to pick up the fob's signal, while a second device near the car relays that signal to it in real time. To the car, it looks exactly like your key is right there — because as far as the signal's concerned, it is.
No damage, no alarm triggered, often no CCTV evidence beyond two people walking up to a car with small devices in hand. It's quiet, quick, and doesn't require the thief to ever touch your actual key.
This isn't a rare, specialist attack — it's become one of the most common ways keyless vehicles are stolen in the UK, precisely because the equipment needed is cheap and the method leaves so little trace.
Why a Factory Alarm Doesn't Stop It
Relay theft doesn't "break in" in any way a standard alarm is designed to detect — no forced entry, no glass breaking, no unauthorised movement before the doors are already open. The car is unlocked and started using what looks, electronically, like the correct key. That's exactly why relay attacks keep working on vehicles with otherwise sophisticated factory security: the vulnerability isn't in the alarm, it's in the wireless handshake between key and car.
What Actually Stops It
The one thing relay attacks can't fake is a second, independent layer that doesn't rely on the key's wireless signal at all. That's exactly what a CAN-bus immobiliser adds: even with a perfectly relayed key signal, the car still won't drive without a PIN sequence or an additional authorised tag — something a relay device has no way to intercept, because it was never transmitted wirelessly by the key in the first place.
- A CAN-bus immobiliser (Ghost, Nitro Pro, or Pandora Microbot) adds authorisation the relay attack can't copy
- A Faraday pouch for your keys blocks the signal at the source — cheap, but easy to forget to use every single time
- A tracker won't stop the theft happening, but gives you a real chance of getting the car back if it does
Layering Protection
The strongest setups combine prevention and recovery: an immobiliser to stop the car being driven away in the first place, and a tracker in case a thief still finds another way around it. Read more in our security buyer's guide.
Curious which vehicles are targeted most in the UK right now? See our breakdown of the UK's most stolen cars, based on real 2025 data.
Quick Questions
Is my car actually at risk of relay theft?
If it has keyless entry, yes — it's worth checking whether your specific make and model has been reported as a common target, but the underlying vulnerability applies to most keyless systems.
Do Faraday pouches actually work?
They block the signal when used correctly, but they rely on you remembering to use one every time, consistently — a fitted immobiliser doesn't depend on you remembering anything.
Will an immobiliser stop every kind of theft?
It's specifically effective against relay theft and key cloning. For full protection, including recovery if a vehicle is taken by other means, pairing it with a tracker is worth considering.
Protect Your Keyless Vehicle
Tell us your make and model, and we'll recommend the right immobiliser for it.
