Motorists across the country have been urgently advised to wrap their car keys in tin foil when not in use, as a simple yet effective countermeasure against a sophisticated form of high-tech vehicle theft. This warning comes in response to a growing trend where tech-savvy criminals exploit wireless technology embedded in modern key fobs to steal cars without ever needing to physically handle the keys or break into homes.
The Rise of Relay Attacks
Known as "relay" theft, this method involves criminals using radio frequency devices to intercept and amplify signals from key fobs. Typically, one thief positions themselves near a home's front door to capture the signal, while an accomplice stands close to the vehicle. The signal is then boosted over a distance, tricking the car into recognising the key as nearby, which allows it to be unlocked and started seamlessly.
This security vulnerability stems from the convenience of contactless key systems, which inadvertently create weaknesses that skilled thieves can exploit. According to recent DVLA statistics, vehicle theft remains a significant issue, with 54,830 vehicles reported stolen in 2025 alone. The Ford Fiesta topped the list with 3,511 thefts, followed by the Volkswagen Golf at 1,625 and the Ford Focus at 1,474.
How Tin Foil Acts as a Shield
To combat these relay attacks, experts recommend using a "Faraday cage," a concept named after 19th-century scientist Michael Faraday, which blocks electromagnetic radiation. While specialised Faraday pouches are available for purchase, wrapping keys in tin foil serves as an immediate and inexpensive alternative. Former FBI agent Holly Hubert highlighted this method in a 2018 interview with the Detroit Free Press, stating, "Although it's not ideal, it is the most inexpensive way. The cyber threat is so dynamic and ever-changing, it's hard for consumers to keep up."
Similar to signal-blocking pouches, tin foil prevents electromagnetic signals from being transmitted, effectively neutralising the threat of relay attacks. Claire Evans, consumer editor at What Car?, emphasised the importance of such precautions, noting, "Annual car theft figures continue to be very high, so owners need to do all they can to keep them safe. Our data shows that small, inexpensive models such as the Nissan Juke and Vauxhall Corsa are under threat, so it's vital to take measures to protect all cars."
Additional Security Measures
Beyond tin foil, other simple measures can significantly reduce the risk of theft. Evans advises using steering locks or keeping car keys in Faraday pouches to lessen the chances of vehicles being stolen. However, relay attacks are not the only tactic employed by criminals. Another method, known as a "CAN bus attack," involves plugging equipment directly into a vehicle's wiring to send fake messages that confuse the system and bypass immobilisers.
The BBC has reported that such devices can be disguised to look like portable Bluetooth speakers, making them difficult to detect. Former Met police officer Vince Wise commented on the evolution of car theft, saying, "Back in the 80s or 90s, it was very easy to get into a vehicle, steal it and take it away. It was probably cheaper than getting a taxi at the time. Now, because of the value of vehicles going up and the demand for parts, it's very easy to move these around and make big profits."
Despite an overall 11 percent decrease in vehicle thefts, relay attacks continue to impact numerous victims, highlighting the need for ongoing vigilance. As criminals utilise relatively low-cost and readily available items like relay boxes, motorists are encouraged to adopt proactive security strategies to safeguard their possessions in an increasingly digital age.
