Blackouts were one of the most pervasive and significant ways in which the war impacted the daily life of British citizens. Air raids at night were one of the most feared aspects of the war, and so the government required that all lights be turned off at night as a precaution against enemy bombers being directed to important targets by the light given off by cities.
For example, in September 1939, regulations required “lighting restrictions.” All street lighting was extinguished. Headlights on vehicles were reduced to slits showing a red light in the front and a white light in the rear. Homes and businesses were only allowed very small apertures in their blackout curtains to allow a small trickle of light to escape.
Blackout curtains were made from tightly-woven fabric and were lined with black paper to prevent the slightest glint of light showing through. Some people found the complete blackout caused by these curtains to be very disorienting.
The blackout restrictions remained in place throughout most of the war. Some cities like London suffered from air raids as late as 1944. The restrictions were finally relaxed in January 1945.