Engineering Hitler's Downfall. Gwilym Roberts

his own test pilot.

      Upon returning to Oxford in 1919 he was appointed a reader in chemical thermodynamics; working on the performance of petrol engines and, he developed octane numbers for rating fuel. In 1919 he was made a member of the Aeronautical Research Committee and the following year he became assistant secretary of the Department of Scientific and Industrial Research which was responsible for co-ordinating the scientific work of the defence and civil departments. In 1933 he was appointed chairman of the Aeronautical Research Committee and two years later chairman of the new Committee for the Scientific Study of Air Defence. These were the bodies that first discussed Robert Watson-Watt's idea for detecting the presence of aircraft by radio beams. The following year he and others resigned from the latter committee as a result of Lindemann's manoeuvres but he continued to take an active part in the development of radar. He encouraged work at the University of Birmingham that led to the invention by John Randall and Harry Boot of the cavity magnetron. This provided the basis for, among other things, centimetric radar, thereby making airborne radar interception possible. In September 1940, with the Battle of Britain at its height, he led a mission to share with the Americans Britain’s scientific and military secrets which proved to be one of the key events in forging the Anglo-American technical alliance in the Second World War. He later played a key part in winning support for Frank Whittle's jet engine. In 1929–42 he was rector of Imperial College London, prior to becoming president of Magdalen College, Oxford, for the following five years.

      Leaving Oxford in 1947, he returned to Whitehall as chairman of the Defence Research Policy Committee and a member of the Advisory Council on Scientific Policy. He retired from government service in 1952 when he became pro-chancellor of the University of Southampton. He died in Hampshire in 1959.

      Tizard’s package was described by an American as ‘the most valuable cargo ever to reach our shores’, while to a Briton ‘the decision to (disclose) all the UK’s secrets, showed great wisdom and boldness’. On their safe arrival in Canada, the two scientists who conveyed the hardware across the Atlantic, John Cockcroft and Taffy Bowen, were shown a pistol by the ship’s captain who told them that he had been instructed, had mishap befallen the ship, to ensure by any means at his disposal that they were not to be taken alive by the enemy.

      Hill, Archibald V. CH OBE FRS (1886–1977)

      A. V. Hill, as he was generally known, was a physiologist and one of the founders of biophysics and of operational research. A Cambridge graduate, he served in the Army in the First World War undertaking ballistics research; his peacetime work was on muscles, for which he was awarded a Nobel Prize in 1922. He was a professor at University College London from 1923 to 1951. In 1935 he worked with Patrick Blackett and Henry Tizard on the committee that gave birth to radar. In 1933, he was a founder member and Vice-President of the Academic Assistance Council (later the Society for the Protection of Science and Learning) which, in particular, assisted refugee Jewish scientists to re-establish themselves in the British academic establishment.

      With Blackett he resigned from Tizard’s Aerial Defence Committee in 1935 because of Lindemann’s manoeuvrings and later was highly critical of his influence on Churchill. Prior to the 1940 Tizard Mission to the USA, Hill went to Washington to sound out his American contacts on their likely reaction to such an initiative; his positive report was a factor in persuading the British Government to proceed with the mission. He knew many leading scientists well, had many influential contacts and, inter alia, recommended Blackett’s appointment to Anti-Aircraft Command. He served as an independent MP for Cambridge University in 1940–45. He took part in many scientific missions to the US. He was appointed OBE in 1918 and also elected FRS; he became a CH in 1946.

      American military science was the responsibility of the National Defense Research Committee, whose establishment was authorised by President Roosevelt after reading a paper by Vannevar Bush, the head of the Carnegie Institution. Bionote in Chapter 10.

      As the USA and UK had a similar approach regarding the scientist-military relationship there was close Anglo-American technical collaboration throughout the war, with nationals from both countries working alongside each other. Often devices developed in the UK were wholly manufactured in the USA; for many weapons and machines this became Britain’s arsenal, with American productive technology manufacturing most of the ships, tanks, aircraft, and armaments that eventually overwhelmed the Axis powers (see Chapter 6).

      The fact that Anglo-American technologists had virtually a free hand to develop novel equipment, coupled with the immense productive capacity of the USA, meant that Anglo-American leaders were blessed with equipment vastly superior to that of their enemies.

      After a mere 21 years of uneasy peace, the world was at war again – a war in which technology would play a crucial role in securing victory for Britain and her allies. Meanwhile in a mansion in Buckinghamshire, many brains were already hard at work trying to decipher the enemy’s messages…

      BLETCHLEY PARK TIMELINE

      The Enigma Encrypting Machine

      1920s German engineer Arthur Scherbius invents the Enigma electro-mechanical encrypting machine. Used commercially and also by several governments, including Germany, to protect military and diplomatic communications.

      1932 Polish mathematician and cryptologist Marian Rejewski partly breaks the German encryption system. French spy working in Germany acquires further information which the French passed to the Poles who are then able to read German messages and build their own replica machines.

      1938 Germans develop a more complex machine which the Poles are unable to read.

      1939 In July the Poles inform French and British cryptologists of their work and, after the outbreak of war, they and their equipment are evacuated to France. They also give one of their replica machines to British cryptologists.

      1940 Following the fall of France, the Poles move first to Vichy, France, and then to Britain in November 1942, where they collaborate with British cryptologists.

      British Decrypting Work

      1938 Government Code and Cypher School (GC&CS) acquires Bletchley Park, Buckinghamshire.

      1939 Recruitment of academics, mathematicians etc. by GC&CS. Separate huts established to tackle the different systems used by each of the German armed forces.

      1940 HMS Griffin captures German trawler. Some naval codes temporarily broken.

      1941 The Germans start using the more sophisticated Lorenz cypher machines. The British name deciphered Lorenz messages Tunny.

      Alan Turing and Gordon Welchman develop a Bombe to speed up decoding procedures.

      In May, a RN ship obtains Enigma machine and code books from a sinking U-boat.

      In December Germany declares war on USA and American cryptologists start working with their British counterparts at Bletchley Park.

      1942–43 Post Office engineer Thomas Flowers builds Colossus which implements Turing/Welchman proposals and enables Lorenz signals to be read more speedily.

      1945 Government orders destruction of all machines.

       Chapter 2

      A BATTLE OF WITS

      Bletchley and beyond

      In 1938 the British Government Code and Cypher School (GC&CS) acquired Bletchley Park, Buckinghamshire (in present-day Milton Keynes) as its headquarters. On the outbreak of war it recruited a number of top-level academics – particularly mathematicians and linguists, but also historians, chess champions, and crossword addicts – to work on decrypting German radio intelligence signals picked up