Around one in 15 plates in circulation could be ghost plates, according to Sky, while a police exercise in London found that 40 per cent of taxi and private hire vehicles had modified plates.
Ghost plates are modified car number plates that reflect light back and stop Automatic Number Plate Recognition (ANPR) cameras from being able to read the figures.
Jack Cousens, head of roads policy for the AA, told Sky: "Drivers manipulating their number plates in any way is a serious offence.
Labour MP Sarah Coombes is trying to change the law to stop counterfeit, illegal number plates being used, by increasing the fine to £1,000.
Politicians are looking to crack down on so-called ghost plates after a reported rise in drivers running red lights and breaking the speed limit.
