From Wikipedia

"This forked symbol was designed for the Direct Action Committee Against Nuclear War (DAC) and was adopted as its badge by the Campaign for Nuclear Disarmament (CND) in Britain, and originally was used by the British nuclear disarmament movement. It was later generalised to become an international icon for the 1960s anti-war movement, and was also adopted by the counterculture of the time. It was designed and completed February 21, 1958 by Gerald Holtom, a professional designer and artist in Britain for the April 4 march planned by DAC from Trafalgar Square, London to the Atomic Weapons Research Establishment at Aldermaston in England[4].


The symbol itself is a combination of the semaphoric signals for the letters "N" and "D," standing for Nuclear Disarmament. In semaphore the letter "N" is formed by a person holding two flags in an upside-down "V," and the letter "D" is formed by holding one flag pointed straight up and the other pointed straight down. These two signals imposed over each other form the shape of the peace symbol. In the original design the lines widened at the edge of the circle.[5]


A conscientious objector who had worked on a farm in Norfolk during the Second World War, Holtom later wrote to Hugh Brock, editor of Peace News, explaining the genesis of his idea in greater depth: "I was in despair. Deep despair. I drew myself: the representative of an individual in despair, with hands palm outstretched outwards and downwards in the manner of Goya's peasant before a firing squad. I formalised the drawing into a line and put a circle round it."