The epidemic of keyless car crime in the past decade has triggered a surge in sales of signal–blocking Faraday pouches and bags, as motorists look to secure vehicles.The gadgets are advertised as the best shield against 'relay attacks' - the most common keyless theft tactic deployed by criminal gangs to pinch motors from owners' driveways without raising the alarm.But while the devices are an effective safeguard, wear and tear can result in them 'expiring', leaving unwitting car owners susceptible to theft, an insurer has warned.The conductive metallic mesh and fabric lining that block electromagnetic fields - such as Wi–Fi, Bluetooth, GPS and cellular signals - can degrade through repeated folding, overfilling with large key fobs, and damage caused by sharp–edged keyrings.When 'Faraday fatigue' occurs, their signal–jamming field becomes compromised, leaving vehicles vulnerable once more.But a new report from Tempcover and Halfords has found that more than a quarter of motorists believe a Faraday pouch is a one–time purchase and don't check that it is still functioning as it should.The short–term car insurer says millions of drivers might be unaware that their devices are a 'ticking timebomb'. Motorists are warned by insurer Tempcover that Faraday pouches and bags designed to act as a shield for keyfobs against keyless car theft can become ineffective through wear and tearAccording to Admiral, around 70 per cent of vehicle thefts today involve keyless cars.But while motorists with Faraday pouches believe they are protected from this type of crime, many will have products that are no longer creating a barrier against theft.Tempcover says they could also become a 'legal liability' for those who fall victim to their flaws.In a poll of 2,000 drivers, it found that 27 per cent believe they are a 'buy–once' product and do not regularly check or replace them over time.Half of the motorists polled wrongly believe that an expired Faraday pouch will still guarantee an insurance payout.In reality, it says owners will be legally exposed under the 'failure to take reasonable care' clause if their vehicle is stolen due to neglected security.Jake Lambert, temporary car insurance expert at Tempcover, said: 'Relying on a degraded pouch that no longer blocks a signal could be seen as a failure of duty.'This doesn't just leave the vehicle vulnerable; it leaves the owner financially exposed, so it's important to ensure you're as protected as possible before a theft occurs by testing regularly.'The poll found that Faraday pouches are used by around 13 per cent of drivers - that's the equivalent of 4.5million of the 34.5million cars on the road.While a quarter claim to test their signal blocker monthly, 27 per cent admit to never checking whether it's successfully blocking their vehicle's signal, and one in 14 say they only test its effectiveness once a year or less often.Halfords says it saw sales of its 'Anti–Theft Car Key Signal Blocker' treble from 2024 to 2025. Yet the average driver is still using a pouch that is over two years old, with 14 per cent having owned theirs for up to five years.Claudia Rennie from Halfords added: 'Faraday pouches are a tried–and–tested technique, but they experience degradation driven by wear and tear, not time on the shelf.'The inner metallic lining - usually a blend of nickel and copper - is what blocks the radio frequency, but it can degrade, crack and rip over time through constant folding.' According to Admiral, around 70% of vehicle thefts in Britain involve keyless carsA new law has recently been introduced to tackle the ongoing issue of keyless car theft and the hi-tech gadgets criminal gangs commonly use to pinch vehicles rapidly and without detection.The Crime and Policing Act 2026 - which received Royal Assent last month - now makes it a criminal offence to manufacture, import, supply, adapt or possess any electronic device that can be used to steal cars.This includes signal relay, repeater or amplifier devices that are widely used by organised and well-funded thieves.These gadgets pick up the signal from the key fob of a car with keyless entry and ignition. Criminals can then remotely unlock and start the car without ever needing to break into a premises to access the keys.The rules also extend to signal jammers - often used by thieves in car parks to prevent a vehicle’s doors from locking when the owner presses the electronic button on the key fob - and illicit tracking devices attached to victims’ cars to monitor their movements.Legislative changes introduced as part of the Act also grant police additional powers to enter premises to search for and seize stolen cars that have been electronically tracked. Top 5 tips to avoid Faraday failure 1. Test frequentlyEvery few months, place your key inside the pouch, seal it, and stand next to your car. If the door unlocks, the pouch needs replacing.2. Keep it dryMoisture compromises conductivity, so keep it dry and never put it in the wash.3. Protect the inner liningBe careful with sharp objects or loose coins, as they can easily rip the delicate inner conductive lining (nickel/copper).4. Avoid overstuffingFilling your pouch to the brim can impact its performance and strain the seams. If you have multiple keys, use separate pouches.5. Park 'Nose–In' Continue to park 'nose–in' against a wall or garage door where possible. This acts as a physical deterrent against technical attacks like 'headlight hacking,' making it significantly harder for thieves to reach the wiring used to bypass security. CARS & MOTORING: ON TEST