Alastair denniston, p.1

Alastair Denniston, page 1


Alastair Denniston

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Alastair Denniston


  Code-breaking From Room 40 to Berkeley Street and the Birth of GCHQ


  Code-breaking From Room 40 to Berkeley Street and the Birth of GCHQ

  Joel Greenberg


  Code-Breaking From room 40 to Berkeley street and the Birth of GCHQ

  First published in 2017 by Frontline Books,

  an imprint of Pen & Sword Books Ltd,

  47 Church Street, Barnsley, S. Yorkshire, S70 2AS

  Copyright © Joel Greenberg, 2017

  The right of Joel Greenberg to be identified as the author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.

  ISBN: 978-1-52670-912-7

  eISBN: 978-1-52670-914-1

  Mobi ISBN: 978-1-52670-913-4

  All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form, or by any means (electronic, mechanical, photocopying, recording or otherwise) without the prior written permission of the publisher. Any person who does any unauthorized act in relation to this publication may be liable to criminal prosecution and civil claims for damages.

  CIP data records for this title are available from the British Library

  For more information on our books, please visit

  email [email protected]

  or write to us at the above address.

  For Robin Denniston and Margaret (‘Y’) Finch






  Chapter 1: A Life in Signals Intelligence

  Chapter 2: British Sigint in World War One

  Chapter 3: Between the Wars

  Chapter 4: Bletchley Park

  Chapter 5: Berkeley Street

  Chapter 6: Cut Loose



  Appendix 1: Charter Documents for Room

  Appendix 2: GC&CS Staff, November 1919

  Appendix 3: Code Text of the Zimmermann Telegram

  Appendix 4: Examples of Room 40 Decrypts with AGD’s Initials

  Appendix 5: How News was Brought from Warsaw at the End of July 1939

  Appendix 6: Approximate Strength of GC&CS on Move to War Station, August 1939

  Appendix 7: Naval Sigint in the UK, December 1940

  Appendix 8: Military Sigint in the UK, December 1940

  Appendix 9: Air Force Sigint in the UK, December 1940

  Appendix 10: GC&CS Diplomatic and Commercial Sections (Civil) Structure in 1944

  Appendix 11: The McCormack Report

  Appendix 12: Denniston/Friedman Correspondence




  Alastair Denniston was not only my favourite uncle but also a very special godfather. How lucky I was that my Mother, always deeply proud of her brother, asked him to undertake this extra duty! It made us especially close.

  This special warm relationship began when I was shipped off to school in Kent at the age of 13. At the beginning of each term he would meet a very fearful child off the train from Leeds at King’s Cross and take me quietly across London to the ‘school train’ at Charing Cross. In spite of the heavy burden he must have been carrying at this time, 1936– 38, he appeared to me to have all the time in the world for a very nervous homesick youngster, chatting warmly about his very special sister (my mother) and all our family ‘doings’, and telling me of the holiday escapades of his beloved son and daughter, my cousins Robin and Y.

  I remember once he told me that he had decided to swap birthdays with his son Robin, who was born on Christmas Day. He and his wife had decided that a small boy should not have to cope with birthday and Christmas Day on the same day, so that was why Robin should always celebrate his birthday on 1 December. He would be very happy to have his on Christmas Day, and so it was until Robin was grown up.

  Holiday times often brought the two families together, either with us up in Yorkshire or in the South. I was invited down to their cottage at Barton-on-Sea. Uncle Alastair met me again in London and the drive down was yet another chance to get to know each other. He said to my mother after one trip that getting me past Walls Ice Cream ‘Stop Me and Buy One’ bicycles was like getting a dog past lamp posts! I remember that the sun always shone at Barton!

  Perhaps one of the happiest and most recent memories of Uncle Alastair was well after the war when he would come up to Yorkshire to stay with my parents in Upper Nidderdale. My father had a grouse moor and shooting days were full of expectation and excitement. Beaters sent out to drive the birds forward were an integral part of the organisation. Uncle Alastair, who had no wish to use a gun, lined himself up with the beaters with his white flag and stumped across the heather. Everyone loved him and you could hear the other beaters call, ‘Come on Uncle Alastair!’ or ‘Are you alright there Uncle Alastair?’ Everyone really enjoyed his company, not remembering that he had won the war for us, but because he was such a genuine quiet loveable person.

  Libby Buchanan


  I first came across the name of Alastair Denniston and a photograph of him while reading the Sunday Telegraph on 21 July 1974. I had just been awarded a PhD in Numerical Mathematics by the University of Manchester and had a passing interest in codes and ciphers. I was immediately drawn to a headline in bold capital letters which said ‘DEEPEST SECRET OF THE WAR’. The paper contained edited extracts from a new book called The Ultra Secret by F.W. Winterbotham. The author had set up the first Scientific Intelligence Unit in his Air Section of the Secret Intelligence Service (SIS) in offices in Broadway near Victoria. Two floors below were the offices of an organisation called the Government Code and Cypher School (GC&CS). According to Winterbotham, it consisted of ‘a dedicated team of highly intellectual individuals under the control of Commander Alastair Denniston’. Denniston was a veteran of the British Admiralty’s codebreaking team during World War One (WW1) and had set up GC&CS. Winterbotham went on to say that when the British discovered that Germany had adopted a cipher machine known as ‘Enigma’, to disguise its operational communications, ‘it was Denniston himself who went to Poland and triumphantly, but in the utmost secrecy, brought back the complete, new, electrically operated Enigma cypher machine which we now knew was being produced in its thousands and was destined to carry all the secret signal traffic of the great war machine’. While Winterbotham’s account of Denniston and the work of GC&CS would later prove to be inaccurate and somewhat fanciful, little did I know that over 38 years later I would meet Denniston’s family and agree to write his biography.

  Denniston’s career in intelligence had begun on the outbreak of war in August 1914 when reservists were called up, and all members of the Royal Navy (RN) began their wartime duties. RN coastal wireless stations began to intercept and forward to the Admiralty wireless traffic of the Imperial German Navy and the task of making sense of this traffic was given to Sir Alfred Ewing, the Director of Naval Education. He gathered together a group of German-speakers who were given Room 40 in the old Admiralty Building to work from. One of his first recruits was Denniston who had been teaching French and German at Osborne Royal Naval College since 1909. At the end of WW1, he was chosen as the RN candidate to head the new GC&CS which had been formed under Admiralty control on 1 November 1919 by a merger of Room 40 and its Army counterpart MI1(b). In the process that followed he was preferre
d to the Army’s candidate and duly appointed Operational Director of GC&CS.

  It seems that the Director of Naval Intelligence during WW1, Admiral Hall, and Admiral Sinclair, Hall’s successor in 1919 and subsequently Chief of the Secret Intelligence Service (SIS) from 1921, felt that Denniston had the right set of skills to manage, encourage, support and develop a set of individual and idiosyncratic staff involved in work which few outsiders understood. He was tasked with producing the vital intelligence which the Prime Minister, the Foreign Secretary and the Secretary of State for War would come to rely on. In 1921, GC&CS became subordinate to the Foreign Office and from 1923 was administered by Sinclair as its Director. During the interwar years, Denniston’s organisation was probably the most effective cryptanalytic bureau the world had ever seen. However, in Denniston’s eyes: ‘Beyond a salary and accommodation vote GC&CS had no financial status; it became in fact an adopted child of the Foreign Office with no family rights, and the poor relation of the SIS, whose peacetime activities left little cash to spare.’ In fact, GC&CS was treated much better than most other branches of government because of the value senior politicians and officials placed on its output.

  In the years that followed the publication of Winterbotham’s book, more information emerged about the activities of GC&CS while based at its war station at Bletchley Park (BP). Denniston had run the operation from 1939 until early 1942 at which point he had been removed from overall command and sent to London to run its much smaller Civil side based in offices in Berkeley Street. However, there was little information in the public domain about Denniston’s Berkeley Street operation. Most authors seemed to concentrate on the period from 1938 to 1945 and activities at BP with a passing reference to the work done by Denniston’s organisation between the wars. The picture that emerged of him was of a man who had set up the BP operation and allowed innovation to flourish, but ultimately, was unable to effectively run it as its requirements for more staff and equipment became increasingly urgent. The circumstances of his removal as Operational Director of GC&CS seemed somewhat obscure. Early accounts were charitable and Ronald Lewin, writing in his book Ultra Goes to War in 1978, said that ‘If it was difficult for Denniston in the early days, it was an even more formidable task for his successor Commander Edward Travis who took over in 1942 after illness caused Denniston, now a veteran warhorse, to be transferred to quieter fields.’ By 1998, GC&CS wartime documents had been released into the public domain and author Michael Smith, in his book Station X, wrote that, ‘No doubt influenced in part by this [problems in the management of Hut 3] and in part by the discontent that had led to the joint letter to Churchill [the famous ‘Action This Day’ letter], Menzies [Head of the SIS and Director of GC&CS] decided that Denniston had neither the political nous nor the force of personality to control the rapidly growing organisation. In order to resolve the problem, he moved him to one side, putting him in charge of diplomatic and commercial codebreaking as Deputy Director (Civilian) with the more dynamic Travis as Deputy Director (Services) in charge of the military sections.’

  In his new role, Denniston established a diplomatic and commercial organisation in Berkeley Street which in effect recreated the GC&CS of the interwar years. This played to his strengths, that of running a smaller group in a very personal and collegiate way. Others could be left to run the codebreaking factory at BP which he had played a key role in creating with the help of colleagues. As German military wireless Enigma traffic diminished in the last few years of the war, diplomatic and commercial traffic continued to increase so that the Berkeley Street operation became a key part of Britain’s signal intelligence (Sigint) effort. American visitors to Berkeley Street produced reports for Washington full of praise for what Denniston was achieving with a small number of staff, both in terms of its scale and quality.

  Ultimately, Denniston’s strategy for consolidating all British Sigint under GC&CS succeeded and by 1944, the organisation had won the right to be in total command of it. Their success from 1940 and onwards won them this right. Therefore, it must have been a bitter pill for Denniston to swallow that he was not allowed to share some of the fruits of this success, given how fundamental his contribution had been. A reorganisation at the end of World War Two (WW2) had made Sir Stewart Menzies (Sinclair’s successor) Director General, with Travis as Director. There was no part for Denniston to play in the future of the organisation which emerged out of GC&CS. He was encouraged out before VJ Day with a pension much smaller than he had expected. He left London and, after a brief spell teaching French and Latin at a prep school in Leatherhead, he retired with his wife to a cottage in the New Forest.

  Denniston died in 1961 at the age of 79 and was buried in Burley in the New Forest. Much to the chagrin of his family, his death was ignored by obituary writers of all the major British newspapers and no acknowledgement was forthcoming from Government Communications Headquarters (GCHQ), the organisation that was born out of his own GC&CS. In 1982, his son Robin decided that the time had come to write a book about his father’s long and distinguished career in intelligence. While former colleagues were keen to contribute, the response from GCHQ and the Defence, Press and Broadcasting Committee was at best, lukewarm. Fighting his failing health, Robin pressed ahead and in 2007, finally published his book, Thirty Secret Years, A.G. Denniston’s work in signals intelligence, 1914-1944.

  In 2009, by now hospitalised, Robin was approached by GCHQ’s Departmental Historian, Tony Comer, who was researching his father’s work during the interwar period. On 6 November 2011, a special memorial service for Denniston was held at St John the Baptist Church, Burley. His grandchildren and other members of the family had organised a short service of rededication in the churchyard at Burley where Denniston was buried. Comer gave the eulogy, in which he summarised Dennison’s achievements as follows:

  His memorial is that he built the UK’s first unified cryptanalytic organisation and developed the values and standards which made it a world leader, an organisation which partners aspired to emulate; and that he personally worked tirelessly to ensure an Anglo-American cryptologic alliance which has outlived and out grown anything even he could have hoped for.

  I first met the Denniston family at an event held at BP on 1 December 2012. As part of the ongoing restoration of the site, it had been decided to recreate Denniston’s office in the Mansion and the family had kindly agreed to donate artefacts to help with the ‘dressing’ of the room. I was asked to take the family on a tour of BP after a short ceremony marking the official handover of the artefacts and a talk by Tony Comer. I had just completed a biography of Gordon Welchman, a Denniston appointment and key member of the GC&CS management team. Welchman had not been treated kindly by the intelligence community after publishing, in 1982, his own account of the work at BP. Both Welchman and Denniston were unknown to the general public and it seemed to me that there was a common theme running through both their lives. On 4 December 2013, Denniston’s family formally opened the exhibition in his old ‘office’ at BP. At that event, it was announced that I had agreed to write the biography of Alastair Denniston with the support of his family and GCHQ.

  Alastair Denniston’s career in intelligence spanned two world wars and ran from the pioneering work of Room 40 to the triumph of BP and the success of Berkeley Street. Between lay the creation of the world’s first cryptanalytic organisation capable of operating on an industrial scale, the famous meeting at Pyry in Poland when French, British and Polish collaboration led to the defeat of Germany’s Enigma cipher system and, arguably, the start of the special relationship between the United States and Great Britain. Yet in the end, something was missing. Those who enter the world of intelligence generally commit to a lifetime of secrecy and anonymity. However, an honours system and other ‘perks’ have been historically used to reward people who have committed a lifetime of service to their country. While some honours came his way, he remains the only Head of GCHQ not to receive a knighthood. He ultimately received scant r
eward for his many years of service to his country.

  It is my hope that this book brings Alastair Denniston’s remarkable career and the story of Sigint to the attention of the general public. While his legacy to the UK and its allies is the organisation that he built, it ultimately outgrew him and, in many respects, he was a victim of his own success.

  Joel Greenberg


  It was a great honour to be entrusted by the family of Alastair Denniston with the task of telling the story of his life and career in signals intelligence. I would like to thank them all, particularly his niece Libby, for their support and providing me with documents and photographs. AGD’s son Robin had researched his father’s career for a number of years. I am grateful to Robin’s son Nick for providing me with all of his father’s research material which he had faithfully kept. When I began this project, Tony Comer, the GCHQ Departmental Historian, offered his support. I am grateful to Tony for reviewing an early draft of the book and providing an official statement on behalf of GCHQ as well as several previously unpublished photographs. I would like to thank my daughters for their ever-present support and love. Finally, I would like to thank the woman in my life for making every day worth living.


  AD(C) Assistant Director (Civil)

  ADIC Assistant Director of the Operational Intelligence Centre Adm Admiralty

  ADMI Assistant Director of Military Intelligence

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