You know those kindly people who flash their lights at you to let you know that there’s a policeman or speed camera up ahead? Well, those people are breaking the law. If you get caught doing the same then you can expect a fine of up to £1,000. Also, there’s no such thing as a 10 per cent leeway for speeding. Doing 33mph in a 30mph zone is just as illegal is doing 45mph.