I'm sure that someone on here will know the answer to this. Whilst following a caravan the other day I noticed that the tow cars mirrors were not able to be seen from a fair distance from the rear. I have to assume that the driver could not see anything in his mirrors except his caravan (as in the sign on the rear of trucks, warning that "If you can't see my mirrors I can't see you"). When I got closer, and on a corner, I could see that at best his mirrors were only the width of his van, but probably narrower. The question is (at last), is there a legal requirement to have mirror extensions ?