It started life as the emblem of the British anti-nuclear movement but it has become an international sign for peace, and arguably the most widely used protest symbol in the world. It has also been adapted, attacked and commercialised.
The logic behind the design was news to us. The designer, Gerald Holtom,
considered using a Christian cross motif but, instead, settled on using letters from the semaphore - or flag-signalling - alphabet, super-imposing N (uclear) on D (isarmament) and placing them within a circle symbolising Earth. [..] Holtom later explained that the design was "to mean a human being in despair" with arms outstretched downwards.
American pacifist Ken Kolsbun, who corresponded with Mr Holtom until his death in 1985, says the designer came to regret the connotation of despair and had wanted the sign inverted.