Police have warned that thieves are using radio signal jammers to steal from cars parked at motorway service stations.

Thames Valley Police said the transmitters could be used to “interrupt” the signal for the remote key, thereby preventing the vehicle from being locked properly.

Police said 14 truck, van and car thefts had been reported recently, but there were “no obvious signs of burglary.”

It advised motorists to check their vehicles before leaving them unattended.

Burglaries were reported in the Chieveley, Reading and Membury service areas on the M4 in Berkshire in the last two weeks of November.

How does a radio jammer work?

The remote key has a unique signal that is transmitted from the remote key to the car via radio waves. Portable jammer suppress the signal from the owner’s key and interfere with this communication.

These devices can be used on a large scale, theoretically allowing thieves to cover an entire parking lot.

Potential thieves rely on drivers to press the lock button on the keychain but forget to double-check that the vehicle is secure, thereby leaving it open for easy access.

More modern vehicles that use keyless entry may also be vulnerable.

Car key Jammer: What you need to know

With tech-savvy thieves reportedly using electronic devices (” key jammers “) to prevent car locks, what do you need to know about this growing crime?

The transmitters, which are easy to buy online, can be used to interrupt the keychain’s signal, meaning careless motorists will think their car is safe when in fact it is not.

This gives thieves an easy way to steal your belongings or even the car itself.

A relatively low-power gps blocker has a range of about 75m, which means that a considerable area (such as an entire parking lot) could be affected at the same time.

But wifi blocker wielding scammers can strike anywhere, not just public parking lots.

Deputy Chief Constable Matt Jukes, of the National Police Chiefs’ Council, said although he believed the problem was minor at the moment, it was “a growing feature of vehicle crime”.

“The Vehicle Crime Intelligence Unit is working closely and extensively with a number of partners, including the Home Office and car manufacturers, to develop solutions to prevent this crime now and in the future.”

Loran Dover contacted the BBC to say the incident had happened to her on a residential street in Leeds.

“When I got up to get ready for work, I went outside and found all the car doors closed.

“When I knew I’d locked the car, I was mortified to think I’d just left it behind – I was staying at my boyfriend’s house and had to leave Christmas presents in the car. But when we actually looked inside, the whole car was ransacked and everything of value had been taken.

“The police initially said they would not take any action. No one was even sent to check for fingerprints, because there were no obvious signs of a break-in. But when I called the bank to cancel my card, the thieves kept using it.” Non-contact type. That’s when the police really got involved and took the matter more seriously.

“They are currently watching CCTV and hopefully they will catch them.”

https://www.youtube.com/watch?v=AX-PD7ffFXY