Even before World War II began, the British Air Ministry had predicted that the United Kingdom would be bombed at night by German air forces. One of the very few precautions the nation could take was the elimination of man-made light. In July 1939 - two months before the declaration of war - the British government distributed Public Information Leaflet No, 2, which set out the need for the general Blackout.

On Aug. 11, 1939, the Blackout began in London, watched by massive crowds of spectators. The nationwide Blackout began on Sept. 1, 1939, two days before the start of the war.