Bidspirit auction | (ENIGMA MACHINE/ULTRA) F. W. WINTERBOTHAM

(ENIGMA MACHINE/ULTRA) F. W. WINTERBOTHAM - Frederick William Winterbotham CBE (1897–1990) RAF officer who supervised the distribution of Ultra intelligence. His book The Ultra Secret was the first popular account of Ultra to be published in Britain. Winterbotham formed 'Special Liaison Units', which were attached to each field headquarters that received Enigma. An SLU consisted of a few RAF officers and enlisted men, low in rank to avoid drawing attention. They received encrypted Ultra messages by radio from Britain, and handed them over to the commander, who was often the only person cleared to know where the information came from. S.P. 3.5 x 5.5 in. b/w, a half-length portrait signed in 1976. Fine.