In the days when an extract from the Construction & Use Regulations was printed in the back of the Highway Code it said that lamps mounted less than 2 feet from the ground could only be used in fog or falling snow. I believe this was later changed to significantly reduced visibility. I know someone who was prosecuted some 10 years ago for using fog lamps in normal conditions. The current regulation states that front or rear fog lights must not be used unless visibility is seriously reduced (generally when you cannot see more than 100 metres). However the recent proliferation of cars driven around with fog lamps on would suggest that plod is turning a blind (dazzled?) eye.
Agree with Graham about rear fog lamps. Yesterday driving back from London in lightly foggy conditions but with tailights visible from about a half mile some 30% on the cars still had their rear fogs on.
