Page 1 ‘Scherbius exhibited his machine’: see David Kahn, The Codebreakers: The Story of Secret Writing, Scribner, New York, 1996, p. 421.
Page 2 ‘Decisive battles have been lost…’: quoted in Ronald Lewin, Ultra Goes to War: The Secret Story, Hutchinson, London, 1978, p. 26.
Page 3 ‘In the case of war…’: quoted ibid., p. 45.
Page 4 ‘Foss painstakingly got down to the problem’: TNA PRO HW 25/10, Hugh Foss’s ‘Reminiscences of Enigma’ (reprinted in Michael Smith and Ralph Erskine (eds), Action This Day: Bletchley Park from the Breaking of the Enigma Code to the Birth of the Modern Computer, Bantam, London, 2001, pp. 42–6).
Page 5 ‘At least 180 letters would be needed’: ibid.
Page 6 ‘Perhaps there was an exhibition’: see Smith and Erskine, Action This Day, p. 44.
Page 7 ‘The methods I used were rather clumsy…’: ibid., p. 45.
Page 8 ‘A jointly run wireless station was set up’: see Nigel West, GCHQ: The Secret Wireless War 1900–86, Weidenfeld & Nicolson, London, 1986, p. 102.
Page 9 ‘Dilly’s colleague Wilfred Bodsworth was impressed’: TNA PRO HW 3/1, Wilfred Bodsworth’s ‘Reminiscences of Naval Section 1927–1939’.
Page 10 ‘The Italian messages were not sent out on the commercial machine he knew’: TNA PRO HW 43/7, extract from the history of ISK (Illicit Services Knox). The full report is still classified.
Page 11 ‘… a remarkable 1,252,962,387,456’: quoted in Graham Keeley, ‘Nazi Enigma machines helped Franco in Civil War’, The Times, 24 October 2008.
Page 12 ‘It was important for the Admiralty’: see Patrick Beesly, Very Special Intelligence: The Story of the Admiralty’s Operational Intelligence Centre 1939–1945, Hamish Hamilton, London, 1977, p. 13.
Page 13 ‘Denning spent several weeks with Dilly’: see Donald McLachlan, Room 39: Naval Intelligence in Action, Weidenfeld & Nicolson, London, 1968, p. 55.
Page 14 ‘A brilliant team for the Second World War’: see Beesly, Very Special Intelligence, for a full account of OIC.
Page 15 ‘Asché returned the precious documents’: see David Kahn, Seizing the Enigma: The Race to Break the German U-boat Codes 1939–1943, Houghton Mifflin, Boston, 1991, p. 59.
Page 16 ‘Impossible to get anything useful…’: quoted ibid., p. 60.
Page 17 ‘An explosion of stupefaction and joy’: Gilbert Bloch, ‘Enigma before Ultra: Polish Work and the French Contribution’, Cryptologia (1987), vol. 11, p. 142.
Page 18 ‘Dilly was already aware of the introduction of the Stecker’: see Robin Denniston, Thirty Secret Years: A.G. Denniston’s Work in Signals Intelligence 1914–1944, Polperro Heritage Press, Clifton-upon-Teme, 2007, p. 107.
Page 19 ‘The discriminants … were isolated by Tiltman’s deputy’: TNA PRO HW 25/10, Cooper’s ‘Pre-history of Enigma’; Denniston, Thirty Secret Years, p. 118.
Page 20 ‘Their cryptographic work is less ambitious than ours…’: TNA PRO HW 25/12, Denniston memo to Strachey, Knox and Tiltman dated 1 November 1938; French minutes of meetings dated 3 November 1938; Denniston to Sinclair, liaison with the French, 2 November 1938.
Page 21 ‘Bertrand “salvaged five Spanish Republicans”’: see Denniston, Thirty Secret Years, pp. 116–17.
Page 22 ‘Dilly might well have broken Enigma’: TNA PRO HW 3/83, ‘Reminiscences of Joshua Cooper’, 1949.
Page 23 ‘A random entry plate connection’: TNA PRO HW 43/70-72, ‘The History of Hut 6’, entry by Dennis Babbage.
Page 24: ‘Dilly brought no information’: Denniston, Thirty Secret Years, pp. 117–18; Smith and Erskine, Action This Day, p. 45; TNA/PRO HW 25/12, assessment by Knox of relative work of the Poles, French and British, 13 January 1939.
Page 25 ‘The French were delighted’: see Smith and Erskine, Action This Day, p. 45.
Page 26 ‘The idea was abandoned’: Denniston, Thirty Secret Years, p. 118; Gustave Bertrand, Enigma ou la plus grande énigme de la guerre 1939–1945, Plon, Paris, 1973, p. 58; TNA PRO 25/12, Denniston to Sinclair, visit to Paris, 13 January 1939; F. H. Hinsley and others, British Intelligence in the Second World War, vol. III, part 2, HMSO, London, 1984, p. 951.
Page 27 ‘He dined at several high tables…’: TNA PRO HW 3/83, ‘Reminiscences of Joshua Cooper’, 1949; Michael Smith, Station X: The Codebreakers of Bletchley Park, Channel 4 Books, London, 1998, p. 16. Station X accompanied the Channel 4 TV series of that name and includes many interviews with former Bletchley Park codebreakers.
Page 28 ‘He sported his oak’: Andrew Hodges, Alan Turing: The Enigma, Simon & Schuster, London, 1983, p. 151.
Chapter 6: The Warsaw conference
Page 1 ‘Godfrey’s mission at that time’: see Donald McLachlan, Room 39: Naval Intelligence in Action, Weidenfeld & Nicolson, London, 1968, p. 15.
Page 2 ‘The 26th (Wednesday) was THE day’: Penelope Fitzgerald, The Knox Brothers, Coward, McCann & Geoghegan, New York, 1977, p. 234; Robin Denniston, Thirty Secret Years: A.G. Denniston’s Work in Signals Intelligence 1914–1944, Polperro Heritage Press, Clifton-upon-Teme, 2007, p. 118; Ralph Erskine, ‘The Poles Reveal Their Secrets: Alastair Denniston’s Account of the July 1939 Meeting at Pyry’, Cryptologia (2006), vol. 30, pp. 294–305.
Page 3 ‘Knox as our expert was alongside Ciężki…’: quoted in Denniston, Thirty Secret Years, pp. 118–20.
Page 4 ‘Knox was really his own bright self…’: quoted ibid.
Page 5 ‘I am fairly clear…’: TNA PRO HW 25/12, Knox to Denniston on Hotel Bristol notepaper, dated only July 1939 but almost certainly 27 July 1939.
Page 6 ‘Just how much Braquenié understood…’: quoted in Władysław Kozaczuk, Enigma: How the German Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two, tr. Christopher Kasparek, University Publications of America, Frederick, MD, 1984, p. 236.
Page 7 ‘Rejewski also recalled the jubilation’: see Józef Garliński, Intercept: The Enigma War, J. M. Dent & Sons, London, 1979, p. 45.
Page 8 ‘Nous avons le QWERTZU’: Michael Smith, Station X: The Codebreakers of Bletchley Park, Channel 4 Books, London, 1998, p. 19.
Page 9 ‘At the time of my visit…’: TNA PRO HW 25/12, Knox memo headed Most Secret, Warsaw, dated 4 August 1939.
Page 10 ‘I hasten to say…’: quoted in F. H. Hinsley and Alan Stripp (eds), Codebreakers: The Inside Story of Bletchley Park, Oxford University Press, Oxford, 1993, p. 127.
Page 11 ‘Accueil triomphal’: see David Kahn, Seizing the Enigma: The Race to Break the German U-boat Codes 1939–1943, Houghton Mifflin, Boston, 1991, p. 81.
Page 12 ‘Rejewski himself had never denied’: TNA PRO HW 25/12; Kozaczuk, Enigma, pp. 258, 312. Oliver Knox recalls that when Turing came to spend weekends at Courns Wood in 1939, his father would be engaged in deep discussions on mathematics with him.
Page 13 ‘It seems that Dilly Knox…’: Gordon Welchman, The Hut Six Story: Breaking the Enigma Codes, Allen Lane, London, 1982, p. 15.
Page 14 ‘Dilly boast to Menzies’: TNA PRO HW 25/12, Knox resignation letter to Brigadier (Menzies), undated.
Page 15 ‘The work they would be doing “did not really need mathematics”’: quoted in Hinsley and Stripp, Codebreakers, p. 113.
Page 16 ‘A few old-time professionals…’: quoted ibid., p. 90.
Page 17 ‘Rejewski had worked out the wiring’: see also Kahn, Seizing the Enigma; Stephen Budiansky, Battle of Wits: The Complete Story of Codebreaking in World War II, Viking, London, 2000, pp. 98–102.
Page 18 ‘The Poles were then able to read messages’: A. P. Mahon, ‘History of Hut 8, 1939–1945’, p. 16, TNA PRO HW 25/2 (reproduced in B. Jack Copeland (ed.), The Essential Turing: Seminal Writings in Computing, Logic, Philosophy, Artificial Intelligence, and Artificial Life, plus the Secrets of Enigma, Clarendon Press, Oxford, 2004, p. 278); C. H. O’D. Alexander, ‘Cryptographic History of Work on the German Naval Enigma’, TNA PRO HW 25/2; Marian Rejewski, ‘How the Polish Mathematicians Broke Enigma’, in Kozaczuk, Enigma.
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Page 19 on ‘boxing’, in which ‘chains’ of related letters were derived from the indicators (the procedure was also known as ‘chaining indicators’), see PRO HW 25/3, ‘Mathematical Theory of ENIGMA Machine by A. M. Turing’ (sometimes referred to as ‘Turing’s Treatise on the Enigma’), pp. 16–19.
Page 20 ‘It would be “possible to find the places”’: TNA PRO HW 25/12, Knox memo headed Most Secret, Warsaw, dated 4 August 1939.
Page 21 ‘These he called “females”’: see F. H. Hinsley and others, British Intelligence in the Second World War, vol. III, part 2, HMSO, London, 1984, p. 951.
Page 22 ‘He “could not possibly have finished the tasks”’: TNA PRO HW 25/12, Knox memo headed Most Secret, Warsaw, dated 4 August 1939.
Chapter 7: Bletchley Park as war station
Page 1 ‘He paid the £7,500 asking price’: see Michael Smith, Station X: The Codebreakers of Bletchley Park, Channel 4 Books, London, 1998, p. 20.
Page 2 ‘A 1920s movie palace…’: Thomas Parrish, The Ultra Americans: The U.S. Role in Breaking the Nazi Codes, Stein & Day, New York, 1986, p. 111.
Page 3 ‘He recruited Richard Gambier-Parry’: see Geoffrey Pidgeon, The Secret Wireless War, UPSO, London, 2003, pp. 50–51.
Page 4 ‘The aerial was slung to the top of a Sequoiadendron giganteum’: see F. H. Hinsley and Alan Stripp (eds), Codebreakers: The Inside Story of Bletchley Park, Oxford University Press, Oxford, 1993, p. 307.
Page 5 ‘“The Park” or more simply “BP”’: TNA PRO HW 14/57. The Wrens based at Woburn and Gayhurst were instructed to stop calling it Station X in November 1942.
Page 6 ‘The chapter on British intelligence’: Richard Deacon and Nigel West, Spy!, BBC, London, 1980, pp. 41–65; Walter Schellenberg, Invasion 1940 (tr. John Erickson), St Ermin’s Press, London, 2000.
Page 7 ‘It fell to my lot’: quoted in Smith, Station X, p. 20.
Page 8 ‘They reached Gustave Bertrand’s wartime Cipher Bureau’: see Józef Garliński, Intercept: The Enigma War, J. M. Dent & Sons, London, 1979, pp. 56–7.
Page 9 ‘The French government were paying for the Polish army’: TNA PRO HW 14/7.
Page 10 ‘I have taken the line…’: TNA PRO HW 25/12, Knox to Denniston, dated 29 September 1939; Penelope Fitzgerald, The Knox Brothers, Coward, McCann & Geoghegan, New York, 1977, p. 199.
Page 11 ‘PC Bruno was also sent copies of the “Jeffreys sheets”’: TNA PRO HW 43/70-72, ‘The History of Hut 6’, Babbage entry, 1:122.
Page 12 ‘Dilly was neither an organisation man nor a technical man’: Gordon Welchman, The Hut Six Story: Breaking the Enigma Codes, Allen Lane, London, 1982, p. 34.
Page 13 ‘I followed suit’: ibid. p. 37.
Page 14 ‘Dilly was furious’: ibid., pp. 54, 71.
Page 15 ‘Hadn’t one said the right thing?’: Fitzgerald, The Knox Brothers, p. 239.
Page 16 ‘Hugh Alexander, the head of Hut 8, later commented’: Michael Smith and Ralph Erskine (eds), Action This Day: Bletchley Park from the Breaking of the Enigma Code to the Birth of the Modern Computer, Bantam, London, 2001, p. 209.
Page 17 ‘He was considered to be part of Dilly’s team’: TNA PRO HW 14/1.
Page 18 ‘Turing is very difficult to anchor down…’: ibid.
Page 19 ‘The information Dilly managed to extract’: TNA PRO HW 25/12. It is described in ‘Turing’s Treatise’, an extract of which appears in B. Jack Copeland (ed.), The Essential Turing: Seminal Writings in Computing, Logic, Philosophy, Artificial Intelligence, and Artificial Life, plus the Secrets of Enigma, Clarendon Press, Oxford, 2004, p. 281.
Page 20 ‘The format FORTYQEETYY’: the Poles had called this the FORTYWEEPY method.
Page 21 ‘He was mechanically apt’: see David Kahn, Seizing the Enigma: The Race to Break the German U-boat Codes 1939–1943, Houghton Mifflin, Boston, 1991, p. 94.
Page 22 ‘This was an electro-mechanical device’: see Władysław Kozaczuk, Enigma: How the German Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two, tr. Christopher Kasparek, University Publications of America, Frederick, MD, 1984, p. 63, n. 1.
Page 23 ‘Which may at any time be cancelled’: TNA PRO HW 25/12, letter from Knox to Denniston, July 1939.
Page 24 ‘This would greatly speed up the breaking of the Enigma messages’: TNA PRO HW 14/2.
Page 25 ‘A meeting on 1 November 1939’: TNA PRO HW 25/12.
Page 26 ‘What happened precisely was this…’: ibid., Knox memorandum dated 3 December 1939.
Page 27 ‘His report to Denniston’: TNA PRO HW 14/12.
Page 28 ‘Welchman had stipulated’: Welchman, The Hut Six Story, p. 76.
Page 29 ‘As yet Turing’s bombes were wishful thinking’: TNA PRO HW 14/1.
Page 30 ‘They resulted from a combination of two different mistakes’: see Smith and Erskine, Action This Day, Appendix IV, ‘Cillies’.
Page 31 ‘Dilly in his playful way called these snakes’: TNA PRO HW 43/70-72, ‘The History of Hut 6’, 1:125.
Page 32 ‘This became known as the “Herivel tip”’: ibid., 1:213; see also John Herivel, Herivelismus and the German Military Enigma, M. & M. Baldwin, Kidderminster, 2008.
Page 33 ‘Testing for self-Stecker’: Smith and Erskine, Action This Day, p. 54.
Page 34 ‘A younger colleague who had specialised in mathematical logic…’: quoted in Copeland, The Essential Turing, p. 235.
Page 35 ‘The Poles had given them some wrong information’: see F. H. Hinsley and others, British Intelligence in the Second World War, vol. III, part 2, HMSO, London, 1984, p. 952.
Page 36 ‘We eagerly awaited the opportunity…’: TNA PRO HW 43/70-72, ‘The History of Hut 6’, 1:126.
Page 37 ‘If there was a crib guess’: ibid., 1:122.
Page 38 Marian Rejewski, ‘Memories of My Work in the Office of Division II, Codes, Chief of Staff, 1930–1945’, Przegląd Historyczno-Wojskowy (2005), no. 5, pp. 132–3. ‘We had the English to thank…’: F. H. Hinsley and others, British Intelligence in the Second World War, vol 3, part 2, p.954 (fn)
Page 39 ‘In the framework of the co-operation…’: Rejewski, ‘Memories of My Work in the Office of Division II, Codes, Chief of Staff, 1930–1945’, p. 133.
Page 40 ‘Bletchley and Bruno audaciously exchanged Enigma secrets’: Kozaczuk, Enigma, p. 87.
Page 41 ‘Knox had been the pioneer worker’: TNA PRO HW 43/70-72, ‘The History of Hut 6’, 1:202.
Chapter 8: Dilly’s girls
Page 1 ‘He was extremely allergic’: TNA PRO HW 14/157, general orders on GC&CS organisation with charts.
Page 2 ‘Another resignation letter’: TNA PRO HW 25/12.
Page 3 ‘My dear Dilly…’: TNA PRO HW 14/22.
Page 4 ‘He had been made chief assistant’: TNA PRO HW 14/1, Butler to Denniston, dated 5 January 1940.
Page 5 ‘Comparable to the operations of the three Services…’: Gill Bennett, Churchill’s Man of Mystery: Desmond Morton and the World of Intelligence, Routledge, London, 2007, p. 177, quoting from TNA PRO FO 837/3, Handbook of Economic Warfare, 24 July 1939. Morton was largely responsible for the creation of the economic intelligence organisation.
Page 6 ‘Their work was devoted to “retrieving the misses”’: TNA PRO HW 25/12.
Page 7 ‘There were catalogues called “corsets”’: TNA PRO HW 25/3, ‘Turing’s Treatise’, Section p. 141.
Page 8 ‘When talking to Lt-Cdr Fleming…’: quoted in B. Jack Copeland (ed.), The Essential Turing: Seminal Writings in Computing, Logic, Philosophy, Artificial Intelligence, and Artificial Life, plus the Secrets of Enigma, Clarendon Press, Oxford, 2004, p. 289.
Page 9 ‘I was frequently asked if I had met the creator of James Bond’: see Mavis Batey, From Bletchley with Love, Bletchley Park Trust, Milton Keynes, 2008, p. 4
Page 10 ‘Prof’s manual was never used in the Cottage’: TNA PRO HW 25/3.
Page 11 ‘Dilly’s XALTX charts’: TNA PRO HW 43/7. The rod techniques described in this chapter mo
stly come from a released extract from the classified history of ISK referring to the Italian machine, which we wrote in 1946.
Chapter 9: The Battle of Matapan
Page 1 ‘A dangerous practice’: see F. W. Winterbotham, The ULTRA Secret, Weidenfeld & Nicolson, London, 1974, p. 18.
Page 2 ‘He set up Special Liaison Units’: see Ronald Lewin, Ultra Goes to War: The Secret Story, Hutchinson, London, 1978, pp. 138–54.
Page 3 ‘So far as the Italian Naval Enigma is concerned…’: TNA PRO HW 14/7, Knox to Denniston, 8 October 1940; Denniston to Knox, 8 October 1940.
Page 4 ‘There is no proper distinction’: TNA PRO HW 25/12, Knox to members of ISK section, dated 3 January 1943.
Page 5 ‘Dilly was a genius in cryptography…’: TNA PRO HW 3/16, Clarke memoir written 1954.
Page 6 ‘Italian Enigma intelligence would go straight from the Cottage’: TNA PRO HW 3/140, Clarke’s ‘Early History of the Naval Section and of Italian Naval Section from 1939 to June 1941’.
Page 7 ‘The Italian invention of the midget submarine’: see F. H. Hinsley and others, British Intelligence in the Second World War, vol. I, HMSO, London, 1979, p. 210.
Page 8 ‘Hut 3 received a decoded Afrika Korps Luftwaffe message’: TNA PRO DEFE 3/686, OL9 21/3/41.
Page 9 ‘I was working in my tiny cabin…’: personal memo to author.
Page 10 ‘Endeavour to make the enemy strike’: TNA PRO ADM 223/88.
Page 11 ‘I have now decided to take 1st BS’: ibid.
Page 12 ‘Destroyed it after perusal’: see Winterbotham, The ULTRA Secret, p. 89.
Page 13 ‘A special signals link had been set up’: F. H. Hinsley and others, British Intelligence in the Second World War, pp. 570–71. For a fuller account of the unit see TNA PRO HW3/165, ‘Hut 3 History’, Chapter V. I am indebted to Wilf Neal for this reference.
Page 14 ‘The conclusion that he decided to sail…’: F. H. Hinsley and others, British Intelligence in the Second World War, p. 405.
Page 15 ‘The Italians continued to intercept’: see John Winton, Cunningham, John Murray, London, 1998, p. 161.
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