THIEVES are arming themselves with high technology gadgets to steal satellite navigation system from cars.
Police have revealed that thieves now know if sat nav systems are in vehicles even if they have been hidden in glove compartments.
The warning follows a spate of thefts across Kirklees.
Det Sgt John Agar, from the Kirklees Vehicle Crime Team, said: "Thieves are using the latest technology, which can track a sat nav system even when it isn't on display in a vehicle.
"If your car is parked up and the sat nav is locked in the glove compartment thieves can still tell it is there and will break into your car.
"Most sat nav systems are small, portable and expensive. They can be used in virtually any vehicle, which makes them particularly attractive to thieves.
"The simplest way to prevent sat nav thefts is to take them out of your car when you leave it. Also, remove the suction pad from the windscreen and hide that. Finally wipe your windscreen down.
"Thieves will often look for marks where the sat nav has been and again break into the car to steal it."
Det Sgt Agar added: "We would also advise motorists to security mark their systems with their house number, postcode and the number of the car, so if the sat nav does get stolen it makes it easier for us to identify and return to the owner.
"It also makes it more difficult for thieves to sell it, as having the identification on it makes the property worthless.
"Just a few moments extra effort from owners can save the expense and inconvenience of replacing equipment and repairing your car."
Some shops offer free security marking to customers when they are sold.
Also, all police stations and Neighbourhood Policing Teams offer free crime prevention advice and property marking.