"Sonya", aka Ruth Werner/Ursula Kuczynski, was one of the 20th century's greatestfemale spies. She died in 2000, never having been exposed. Operating in Britain during the Second World War, she passed Washington's atomic secrets to Moscow. In this programme her son, Michael Hamburger- himself a leading GDR dissident and intellectual -tells her Story for the first time. Producer Rosie Goldsmith