Layout 8 - Winston Churchill

Intelligence: In the Great Drama,They Were the GreatestSEE ALSO ALAN TURING (BACK COVER)THOMAS H. FLOWERS (1905-1998)was the father of Colossus, theworld’s first programmable computer,which helped solve the encryptedGerman messages. It was Flowerswho provided the secret decrypts toEisenhower the day before D-Day,revealing that Hitler was moving noadditional troops to Normandy,believing it was not the target.JOHN TILTMAN (1894-1982) hadworked with British Intelligence sincethe 1920s. Brigadier Tiltman had madea series of major breakthroughsagainst Japanese military cyphers from1933 onwards. A strong advocate ofBritish cryptology cooperation with theUnited States, he was affectionatelyknown to both sides as “The Brig.”HUGH O’D. ALEXANDER (1909-1974)was an Irish-born cryptanalyst morefamous after the war as a master chessplayer. Arriving at Bletchley Park inFebruary 1940, he played a key role atHut 6, which broke the German Armyand Air Force Enigma messages; then,at Hut 8, he broke the Naval Enigma.After the war he assisted MI5 in theVenona project to break Soviet codes.MAX H.A. NEWMAN (1897-1984), amathematician, was a pioneer of electronicdigital computing. In 1943 heheaded a new Bletchley section tocounter the German Tunny teleprintercypher device, increasingly used byHitler and his top command after 1941,when they began to suspect Enigmawas compromised.WILLIAM GORDON WELCHMAN(1906-1985), a British-American mathematicianand professor, came toBletchley from Cambridge. He was oneof the four “Wicked Uncles” (withAlexander, Turing and Stuart Milner-Barry) who in October 1941 urged thePM to provide more resources toBletchley. Churchill responded.TELFORD TAYLOR (1908-1998) joined U.S.Army Intelligence as a Major in 1942 and ledthe American analysis of German communicationsusing shared British Ultra encryptions.In 1943 he helped negotiate the Anglo-American BRUSA Agreement, secret until themid-1990s. A lawyer, Taylor was a prosecutioncounsel at the Nuremberg Trials of Naziwar criminals. In the 1950s he was an outspokencritic of Senator Joseph McCarthyand, in the 1960s, of the war in Vietnam.on the following day: “The American Naval Authoritieshave been given several of our Cypher Machines.” 15In May 1942, Churchill approved Menzies’ agreementto help OP-20-G to work on the “Shark” key and otherGerman Enigma circuits. OP-20-G eventually built morethan a hundred four-rotor bombes that proved invaluable insolving—between June 1943 and April 1945—not only2940 German Naval Enigma keys, but also 1600 GermanArmy and Air Force Enigma keys, all of which were thenread at Bletchley without interruption. 16In June 1942, General Dwight D. Eisenhower arrivedin Britain as Commander-in-Chief of the United StatesForces then being assembled as a prelude to a cross-Channelassault. Churchill invited him to Chequers, where he personallybriefed him on the work being done at Bletchley, towhich, as a Commander-in-Chief, he would have access. 17On 17 May 1943 the British-United States Agreement(BRUSA) was signed between Bletchley Park and theUnited States War Department. This came to be known asthe “written constitution” of Anglo-American cryptanalysis.18 Its aim was “to exchange completely allinformation concerning the detection, identification andinterception of signals from, and the solution of codes andcyphers used by, the Military and Air forces of the Axispowers, including secret services (Abwehr).” The UnitedStates assumed the “main responsibility” for the reading ofJapanese military and air codes and cyphers (Magic), theBritish for reading the German and Italian signals traffic(Ultra). There would be total reciprocity, and total secrecy. 19Following this agreement, Colonel Alfred McCormackand Lieutenant-Colonel Telford Taylor, from the UnitedStates Army’s Special Branch, were sent to Bletchley to seehow the system there operated. It was not until September1943, however, that Churchill finally persuaded Menziesthat the BRUSA agreement should be operated without anyrestrictions, and that the United States Army in Washingtonshould be sent—without restriction—all British SignalsIntelligence material, including the Enigma andGeheimschreiber decrypts. 20Riddle of the BalkansEnigma-based knowledge was continuous, and calledfor many difficult decisions. The most difficult to confrontChurchill and the War Cabinet, and those in receipt ofEnigma-based information, related to the Balkans. In thelast week of October and the first few days of November1940, Enigma decrypts had made it clear that the GermanAir Force was building up facilities for German aircraft usein Romania and Bulgaria, both on the Danube and theBlack Sea. 21 This information was set out in a War Cabinetpaper on 5 November 1940. 22The possibility of a German attack on Greece, withwhom Britain had a treaty of alliance, meant that Britishmilitary, naval and air forces then protecting Egypt from >>FINEST HOUR 149 / 23