Joel Greenberg - Alastair Denniston: Code-Breaking from Room 40 to Berkeley Street and the Birth of GCHQ

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

ALASTAIR DENNISTON:

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

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For Robin Denniston and Margaret (Y) Finch

A lastair 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 Kings 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 Admiraltys 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 Winterbothams 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 Dennistons family and agree to write his biography.

Dennistons 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 preferred to the Armys candidate and duly appointed Operational Director of GC&CS.