Controversial: Naeem Khokhar (pictured), of CBS Automotive, demonstrates how the device works

UK distributor CBS Automotive claims it will prevent accidents by alerting drivers to emergency vehicles rushing to incidents. But last night Gwent Police Crime Commissioner Ian Johnston called for them to be banned.

He said: ‘This device is a passport to villainy and there is no legitimate reason for a law-abiding person to have one. The sellers are being very naive if they believe that they will be used to reduce accidents.

‘A criminal will carry out a drug deal, see a light on their dashboard and then ditch their illegal stash, only to pick it up when the police aren’t around – or a motorist will be speeding on the motorway, an alert will pop up and they’ll slow down.’

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.

The Mail on Sunday took a red Vauxhall Corsa fitted with the device for a test drive on Friday with Naeem Khokhar, the managing director of CBS Automotive. The device’s aerial was concealed behind the car’s rear-view mirror while its control box was hidden in the glovebox. The LED alert panel was mounted next to the car’s controls. As we pulled out of the firm’s Cambridge headquarters, the device automatically started registering two lights out of five.

Mr Khokhar said it was likely that it had been set off by the British Transport Police officers, who are stationed close to his office. As we drove along the street, the panel’s lights flashed again – this time the cause was a traffic warden.

The Target Blue Eye (pictured) uses different coloured lights to warn of police cars' proximity

Its UK distributor claims it will prevent accidents by altering motorists to emergency vehicles rushing to the scene of accidents

The Target Blu Eye emits a beep when a vehicle is within range and a double-beep if the radio is transmitting data – meaning that emergency service personnel are talking over the radio. We parked near to ambulances at Addenbrooke’s Hospital and all five lights lit up.

Mr Khokhar said: ‘There have been times when I’ve stopped at traffic lights and the Blu Eye starts going off but I can’t see any other vehicles. I have then driven off and seen a police car behind a bush.’

Mr Khokhar denied there was potential for the devices to be used for criminal activity. He said: ‘If anything, these devices are a criminal prevention tool. If you are planning to carry out a crime where there are emergency vehicles and the device is going off then you wouldn’t dare go through with it.’

But Steve Evans, vice-chairman of the Police Federation of England and Wales, said: ‘We have grave concerns about any product that may be used to compromise police officers’ or public safety.’

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.’