From the 1 September 1939 the black-out of Britain began. Every window in every building had to be covered by the fall of dark, so that no light could be seen from the outside. When the 'Blitz' began this was especially important, because it made it more difficult for the German bombers to find their targets. Headlamp covers (such as the one shown here) were placed over car lamps for the same reason and there were heavy fines for people not complying with the rules.