The BBC's Watchdog programme last night revealed how high-tech scanners are being used by criminals to re-programme the electronic keys of executive cars in order to steal them.

Among the models most at risk from the practice are Audis, BMWs and Range Rovers - according to the programme makers.

The scanners, which can be bought online quickly and easily, can be used to unlock a target vehicle in under a minute.

One type of scanner is used to unlock the door, while a different type is required to start the engine.

Makers of the TV show have come under fire from some quarters for making knowledge of the scanning technology more widespread, while others argue that the show highlights a serious problem that needs to be tackled.

Some manufacturers are angry that the government has not done more to ban the sale of the technology, which is sometimes used by roadside assistance operators in order to help customers gain access to their vehicle if they have been locked out.

Carmakers also blamed the EU for making crucial coding data easy to access.

In London alone more than 1,000 vehicles have been stolen in this way over the last 12 months.

A Watchdog spokesman said: “A demonstration for the programme shows how a BMW X6 key can be programmed in just 12 minutes, an Audi A5 in just 40 seconds and a Range Rover Evoque in just 10 seconds.”

By Craig Hindmarsh