Yob Carl Bennett breaks his way in to the vehicle, thinking the dozy driver had left his hi-tech navigator on display.

Little did he know it was a police decoy car, fitted with the latest equipment to snare thieves. He spends just seconds leaning into the car, which was parked in Wednesbury, as he frantically rummages around for valuables before leaving with the sat nav under his arm.

But officers took just seconds to recognise him and came knocking on his door.

The 30-year-old, from Bridge Street, Bilston, was later jailed for 17 weeks at Warley Magistrates Court for theft.

Today it emerged West Midlands Police are stepping up the fight against thieves by bugging the sat navs themselves. Officers are leaving decoy vehicles containing the expensive gadgets in crime hotspots.

Once a decoy vehicle, known as a capture car, is tampered with, video equipment grabs images and a message is sent to nearby officers via satellite.

Thieves can be locked in as soon as they enter the car, which is watched by nearby undercover officers.

Det Ch Insp Danny Long, from West Bromwich police, said: “With the capture car, we can lift the car thief.

“But now we’ve got new technology which means we can actually put a track on the sat nav, pick it up and know where it’s going so we can lift the handlers as well.

“It may go through one, two or three people before it ends up with a customer. Now we can track all those people.

“It’s an attempt to dry up the market once people realise these sat navs have also got a sat nav on them. Sat navs are the commodity of the day. This is good technology and a number of people have already been arrested as a result of it.” Dozens of postcards are now being hand delivered to prolific car thieves warning them of the new technology. They show a sat nav holder displaying a map giving directions to jail. The technique is being used as part of Operation Momentum, targeting traditional autumn rises in crime.

Earlier this month, police revealed that Wolverhampton was one of the region’s sat nav crime hotspots.

An average of 331 of the gadgets are stolen each month across the West Midlands, but August saw a sharp rise with 503 thefts.

Police hope the images will persuade owners to remove all valuables from unattended cars.