A new gadget will allow drivers who spot a speed camera to alert other drivers of its location within three seconds.
The device, which its makers say exploits a loophole in the law, transmits the location of the speed trap to a processing centre. The information is then relayed to other drivers who have the same equipment in their cars.
The device, called the Novus Mini Coyote, emits an alarm and a colour-coded warning telling the driver how frequently the speed trap has been reported. It also displays the cars speed, the speed limit and distance to the camera.
Police forces warn that drivers could be prosecuted for perverting the course of justice if they try to alert other motorists to speed traps, but there have been very few successful prosecutions.
Nigel Carter, managing director of Novus, said: 'This is actually a road safety device because it will help prevent accidents caused by drivers stamping on the brakes when they spot a camera too late. As far as we can see, there is nothing illegal in the unit.'