SIR, How curious that Kevin Tea of Cumbria Safety Cameras (Letters, February 6) is at pains to assure drivers that they will not receive a ticket for doing 33mph in a 30mph limit, then says he operates according to a threshold recommended by the Association of Chief Police Officers, but cannot bring himself to say what that threshold is. This is deliberate obfuscation which no doubt infuriates some of your correspondents in the speed camera debate. J.N. Torrance (Letters, February 6) is right; the threshold is ten per cent plus two mph. Therefore, according to Kevin Tea, 33mph in a 30mph limit is acceptable but 35mph is, in his words, one of the "more significant infringements". This is gobbledegook.

Peter Wood Natland