The Making of Bletchley Park and Signals Intelligence 1939–42

Abstract

The article argues that signals intelligence was an organizational accomplishment in the sense of requiring a) the establishment of an independent organization and b) that this organization combine cryptanalysis with intelligence analysis, traffic analysis and interception. This was not pre-ordained but the outcome of specific conflicts and decisions at Bletchley Park during the first three years of the Second World War which transformed the Government Code and Cypher School from a cryptanalytical bureau to a fully-fledged signals intelligence agency. Detailed archival evidence is presented in support of this claim.

Acknowledgements

The work on which this article is based was undertaken as part of a Leverhulme Major Research Fellowship, funded by the Leverhulme Trust, whose support is gratefully acknowledged. The comments of two anonymous referees for INS are also very much appreciated.

Notes

¹More properly a fully-fledged Sigint organization is also engaged in cipher security or communications security (Comsec). GC & CS was generally neglectful of this ‘defensive’ aspect of Sigint and was primarily focused on ‘offensive Sigint’ (i.e. codebreaking and its exploitation). Comsec issues are beyond the scope of this article and when, for reasons of concision, I refer to the development of GC & CS as a Sigint organization this should be taken to mean, specifically, an ‘offensive Sigint organization’. See R. Ratcliff, Delusions of Intelligence: Enigma, Ultra and the End of Secure Ciphers (New York: Cambridge University Press 2006) pp.159–79 for discussion of GC & CS's neglect of Comsec. Organizational issues around Comsec at GC & CS is an area which would repay further research.

²Christopher Grey, Decoding Organization: Bletchley Park, Codebreaking and Organization Studies (Cambridge: Cambridge University Press 2012).

³Strictly speaking, NID 25.

⁴M. Smith, Station X: The Codebreakers of Bletchley Park (Basingstoke: Macmillan1998) p.17.

⁵See R. Denniston, Thirty Secret Years: A.G. Denniston's Work in Signals Intelligence 1914–1944 (Clifton-upon-Teme: Polperro Heritage Press 2007) pp.54–5 for the full text of GC & CS's 1919 remit.

⁶Churchill College Archives Cambridge DENN 1/4: 2. For more detail on GC & CS finances see E. O'Halpin, ‘Financing British Intelligence: The Evidence up to 1945’ in K.G. Robertson (ed.) British and American Approaches to Intelligence (Basingstoke: Macmillan 1987) pp.187–217 and K. Jeffery, MI6: The History of the Secret Intelligence Service 1909–1949 (London: Bloomsbury 2010) p.475.

⁷H. Hinsley, British Intelligence in the Second World War, abridged ed. (London: HMSO 1993) p.5.

⁸Whitehall is a generic term for the British government and more specifically for the permanent civil service administration of the state as opposed to politicians.

⁹TNA HW 43/1: 145.

¹⁰TNA HW 43/1: 176.

¹¹H. Hinsley, E. Thomas, C. Ransom and R. Knight, British Intelligence in the Second World War: Its Influence on Strategy and Operations, Vol. 1 (London: HMSO 1979) p.273.

¹²TNA HW 14/145: 22. Nigel de Grey was second in command at BP from 1942 and in 1949 compiled a detailed review of its wartime operations and organization.

¹³P. Davies, ‘From Amateurs to Professionals: GC and CS and Institution-building in Sigint’ in M. Smith and R. Erskine (eds.) Action this Day (London: Bantam 2001) pp.386–402, p.395.

¹⁴S. Budiansky, Battle of Wits: The Complete Story of Codebreaking in World War II (London: Viking 2000) p.229.

¹⁵TNA HW 14/154.

¹⁶As in Nigel de Grey's post-war review, TNA HW 14/145: 14.

¹⁷TNA HW 14/67: 1.

¹⁸TNA HW 43/2: 468.

¹⁹TNA WO 208/5070.

²⁰TNA WO 208/5070: 11.

²¹5 September 1939, TNA HW 14/1.

²²TNA HW 43/2: 469.

²³Davies, ‘From Amateurs to Professionals’, pp.395–6.

²⁴TNA HW 43/2: 474. The quote is from de Grey but the document in which it is quoted is Birch's internal history of Sigint rather than de Grey's post-war review.

²⁵See C. Grey and A. Sturdy, ‘The 1942 Re-organization of GC and CS’, Cryptologia 32/4 (2008), pp.311–33 for more detail on the organizational impact of the Trafalgar Day letter.

²⁶See for example Grey and Sturdy, ‘The 1942 Re-organization of GC and CS’, p.327.

²⁷TNA HW 14/145: 5 and 8.

²⁸Summary of TNA HW 14/145: 5–10, the quotation is from p.10.

²⁹TNA HW 14/61. The individuals in question were, respectively (then) Wing Commander Eric Jones and Gordon Welchman.

³⁰TNA HW 43/2: 478.

³¹TNA HW 14/145: 5.

³²TNA HW 14/145: 9.

³³G. Welchman, The Hut Six Story: Breaking the Enigma Codes (London: Penguin 1982) p.147.

³⁴TNA HW 14/145: 22.

³⁵TNA HW 43/2: 473–4.

³⁶See Hinsley, Thomas, Ransom and Knight, British Intelligence in the Second World War, pp.267–74 for more extensive detail.

³⁷TNA HW 43/1: 180–202.

³⁸17 December 1940, TNA WO 208/5130.

³⁹4 January 1941, TNA WO 208/5130.

⁴⁰3 February 1941, TNA WO 208/5130.

⁴¹Davies, ‘From Amateurs to Professionals’, p.399.

⁴²TNA WO 208/5130: 10a.

⁴³Hinsley, Thomas, Ransom and Knight, British Intelligence in the Second World War, p.272.

⁴⁴TNA HW 14/16.

⁴⁵TNA WO 165/38.

⁴⁶TNA HW 14/24.

⁴⁷TNA WO 208/5070.

⁴⁸Hinsley, Thomas, Ransom and Knight, British Intelligence in the Second World War, pp.268–9.

⁴⁹TNA HW 43/1: 201–2. This document is hereafter referred to as the internal history of Sigint.

⁵⁰TNA HW 25/2 and TNA HW 43/1: 195.

⁵¹P. Beesly, Very Special Intelligence: The Story of the Admiralty's Operational Intelligence Centre 1939–45, reissued ed. (London: Greenhill Books 2000 [1977]) p.9.

⁵²In the early months of the war this by no means smooth, with NS suggestions being met on occasion with ‘something ranging from indifference to contempt’ (Budiansky, Battle of Wits, p.147).

⁵³Beesly, Very Special Intelligence, p.22.

⁵⁴Hinsley, Thomas, Ransom and Knight, British Intelligence in the Second World War, p.268; Beesly, Very Special Intelligence, p.69.

⁵⁵TNA HW 3/16.

⁵⁶Cited in Budiansky, Battle of Wits, p.202.

⁵⁷TNA HW 3/134: 4.

⁵⁸TNA HW 3/134: 68.

⁵⁹Beesly, Very Special Intelligence, p.255.

⁶⁰TNA HW 43/1: 431.

⁶¹I am skating over a good deal of complexity here. See Hinsley, Thomas, Ransom and Knight, British Intelligence in the Second World War, pp.267–8 and Beesly, Very Special Intelligence, for more detail.

⁶²TNA HW 14/67: 5.

⁶³See P. Calvocoressi, Top Secret Ultra, 2nd ed. (Kidderminster: Baldwin 2001); R. Bennett, ‘The Duty Officer, Hut 3’ in H. Hinsley and A. Stripp A. (eds.) Codebreakers: The Inside Story of Bletchley Park (Oxford: Oxford University Press 1993) pp.30–40.

⁶⁴TNA HW 3/119: 37.

⁶⁵Head of Naval Section, in succession to W.E. Clarke, see above.

⁶⁶18 November 1941, TNA HW 8/23. See also TNA HW 3/119: 4–6.

⁶⁷TNA 43/1: 440.

⁶⁸Bennett, ‘The Duty Officer, Hut 3’, p.31.

⁶⁹TNA HW 43/1: 439.

⁷⁰Smith, Station X, p.92.

⁷¹TNA HW 3/119: 34.

⁷²15 December 1941, TNA HW 14/24.

⁷³2 January 1942, TNA HW 14/26. See also TNA HW 43/1: 441.

⁷⁴TNA HW 43/1: 440.

⁷⁵TNA HW 3/119: 37.

⁷⁶1 November 1942, TNA HW 14/22, emphasis in original.

⁷⁷TNA HW 43/1: 441.

⁷⁸TNA WO 208/5070.

⁷⁹TNA HW 43/2: 493.

⁸⁰The replacement of Denniston with Travis was part of a far-reaching re-organization of GC & CS in 1942, following the Van Cutsem report. This was intimately connected with the themes of this article but cannot be discussed for reasons of space. For a detailed account, see Grey and Sturdy, ‘The 1942 Re-organization of GC and CS’.

⁸¹TNA HW 14/67: 5.

⁸²R. Lewin, Ultra Goes to War, reissued ed. (Barnsley: Pen and Sword Military 2008 [1978]) p.65.

⁸³All quotations extracts from TNA 43/1: 452–7.

⁸⁴TNA HW 3/95.

⁸⁵TNA HW 43/70: 5.

⁸⁶Enigma aside, this issue initially limited the effective use of low-grade GAF Sigint. See A. Bonsall, ‘Bletchley Park and the RAF Y Service: Some Recollections’, Intelligence and National Security 23/6 (2008) pp.827–41.

⁸⁷10 January 1941, TNA HW 14/10.

⁸⁸TNA HW 3/119: 25–6.

⁸⁹See for example TNA WO 208/5071.

⁹⁰Hinsley, British Intelligence in the Second World War, p.6.

⁹¹TNA HW 3/83: 7.

⁹²J. Thirsk, ‘Traffic Analysis: A Log-reader's Tale’ in M. Smith and R. Erskine (eds.) Action This Day (London: Bantam 2001) pp.264–77. Quotation is from Ralph Erskine's editorial introduction to the chapter, p.265.

⁹³Welchman, The Hut Six Story, p.76.

⁹⁴Hinsley, Thomas, Ransom and Knight, British Intelligence in the Second World War, p.268.

⁹⁵Davies, ‘From Amateurs to Professionals’, p.399.

⁹⁶TNA HW 14/40.

⁹⁷TNA HW 14/71: 2.

⁹⁸E.g. 5 July 1944, TNA HW 14/107.

⁹⁹TNA WO 208/5070: 5.

¹⁰⁰Welchman, The Hut Six Story, p.156. Although Welchman and others were supportive of some forms of TA when directly relevant to the Enigma effort.

¹⁰¹TNA HW 3/92: 14. Not to be confused with Birch's internal history of Sigint.

¹⁰²Hinsley, Thomas, Ransom and Knight, British Intelligence in the Second World War, p.270.

¹⁰³Quoted in Birch's internal history of Sigint, TNA HW 43/1: 186–7.

¹⁰⁴TNA HW 43/1: 187.

¹⁰⁵Welchman, The Hut Six Story, pp.56–7.

¹⁰⁶Ibid., p.87.

¹⁰⁷Ibid., p.89.

¹⁰⁸Ibid., pp.120–1.

¹⁰⁹Ibid., p.120.

¹¹⁰TNA HW 25/1: 87.

¹¹¹E.g. Smith, Station X; Lewin, Ultra Goes to War; Ratcliff, Delusions of Intelligence.

¹¹²TNA HW 43/70.

¹¹³P.S. Milner-Barry, ‘In Memoriam W. Gordon Welchman’, Intelligence and National Security 1/2 (1986), p.141.

¹¹⁴November 1 1942, TNA HW 14/22, emphasis in original.

¹¹⁵For example, Bonsall (‘Bletchley Park and the RAF Y Service’, p.827) suggests in relation to low-grade GAF ciphers that the AM's adherence to a division between producers and users of intelligence ‘led it to obstruct the production of some of this intelligence for nearly half the war’. But, again, this situation shifted as Sigint developed in the way outlined here.

¹¹⁶M. Freedman, Unravelling Enigma: Winning the Code War at Station X (Barnsley: Pen and Sword Military 2000) p.180.

¹¹⁷Hinsley, Thomas, Ransom and Knight, British Intelligence in the Second World War, p.21n.

¹¹⁸TNA HW 43/1: 180.

¹¹⁹M. Batey, Dilly: The Man Who Broke Enigmas (London: Biteback Publishing 2010) p.88.

¹²⁰TNA HW 43/1: 180. The term ‘special intelligence’ did continue to be used by the OIC, however, to refer to Ultra intelligence; Beesly, Very Special Intelligence.

¹²¹TNA HW 14/66.

¹²²TNA HW 14/67: 1.

¹²³This is presumably intended ironically, as BP's capacity to be ‘master in its own house’ had been achieved in the face of opposition from the ministries.

¹²⁴TNA HW 14/67: 10.

¹²⁵TNA HW 43/1: 455–7.