Incidents of remote jamming have been reported again, so be alert when leaving your vehicle in a public place. Car remote controls use a radio frequency that is often the same as for gate and garage opening devices. When the device receives two messages simultaneously – from the driver and the criminal – it cannot correctly interpret the ‘lock’ instruction and so no action is taken. There are also ‘professional’ jamming devices with stronger signal power that can influence a remote control from further away (so criminals can stay out of sight). Never use the remote ‘lock’ instruction while walking away from the vehicle: stand next to it and manually check the doors and boot are locked. Don’t leave tempting valuables such as briefcases, shopping packets and cameras in plain sight – lock them in the boot before leaving your previous destination.