It's a case of chip and sin. Thieves have invented a new way to steal cars - by removing the key's transponder microchip and hiding it next to the ignition. This permanently disables the immobiliser, and the crook sells the car with the official keys, so the buyer is unaware.

They then steal it back using a copy cut by a high street locksmith, which starts the disarmed engine. Vehicle crime expert Phil Swift of Claims Management and Adjusting, in West Malling, Kent, said: "It's now a very common method - 100 cars have been taken in this way in Manchester alone."