There has been widespread advertising of the plates in the motoring press, but Mr Carlisle told motorists they were wasting their money and could be liable to additional penalties if they bought and used them.
He insisted in a Commons written reply that the plates were ineffective in aiming to foil speed check cameras by merging numbers and letters with the background in any photographs.
He said: 'Reflective number plates designed to evade speed camera technology do not work. Photographs of such plates taken by approved speed detection equipment show the number quite clearly and the offence can be followed up in the normal manner.
'Use of these plates is illegal and the photographs also provide evidence of this offence.'
Mr Carlisle said it would become illegal to offer for sale any plates which did not comply with British Standard regulations, to be published soon.Reuse content