• The dashboard-mounted Target Blu Eye picks up encoded radio signals
• It can detect police cars, including unmarked vehicles, half a mile away
• The device uses coloured lights according to warn of police cars’ proximity
• But crime commissioner Ian Johnston has called for device to be banned
• He said there was no legitimate reason for a law-abiding citizen to own one

A gadget that alerts speeding drivers when police cares and emergency vehicles are nearby was last night facing calls by police and motoring organisations to be banned in the UK.

The £999 Target Blu Eye is a dashboard-mounted device which, astonishingly, is perfectly legal, according to its makers.Devices that detect the position of speed cameras are legal for use on UK roads. Several years ago, legislation was proposed to make detectors with radar and laser illegal, but the ban did not go ahead.

It can detect when police cars – even unmarked vehicles – are more than half a mile away by picking up encoded radio signals, and then sends a warning to the motorist.The device uses coloured lights according to warn of police cars’ proximity

AA spokesman Luke Bosdet added: ‘The only person who will have one of these fitted to their cars is the type of person who is trying to dodge the law.’