Yesterday was the 70th anniversary of the launch of Winston Churchill's WWII "V for Victory" campaign. To mark the occasion, LIFE.com gathered up color photos taken in London during the war.
From LIFE.com: "I felt," Churchill recalled, "with a spasm of mental pain, a deep sense of the strain and suffering that was being borne throughout the world's largest capital city. How long would it go on? How much more would they have to bear? What were the limits of their vitality? What effects would their exhaustion have upon our productive war-making power?"
A man sits on a park bench in London, reading a book; a moored "barrage balloon" is visible in the background, while a second one soars high in the distance. Barrage balloons were remarkable devices designed to fly high enough to disable or even destroy enemy aircraft, which might fly into their ropes and metal cables. In WWII, barrage balloons were credited with bringing down more than 200 V-1 flying bombs -- or "doodlebugs," as the enormous (4,000-lb.) weapons were known in characteristically blithe British vernacular -- over England during the Blitz.
Lots more color photos of London in this LIFE.com gallery.