CHURCHILL’S DIPLOMATIC EAVESDROPPING AND SECRET SIGNALS INTELLIGENCE AS AN INSTRUMENT OF BRITISH FOREIGN POLICY, 1941-1944: THE CASE OF TURKEY Submitted for the Degree of Ph.D. Department of History University College London by ROBIN DENNISTON M.A. (Oxon) M.Sc. (Edin) ProQuest Number: 10106668 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest. ProQuest 10106668 Published by ProQuest LLC(2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. Microform Edition © ProQuest LLC. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 2 ABSTRACT Churchill's interest in secret signals intelligence (sigint) is now common knowledge, but his use of intercepted diplomatic telegrams (bjs) in World War Two has only become apparent with the release in 1994 of his regular supply of Ultra, the DIR/C Archive. Churchill proves to have been a voracious reader of diplomatic intercepts from 1941-44, and used them as part of his communication with the Foreign Office. This thesis establishes the value of these intercepts (particularly those Turkey- sourced) in supplying Churchill and the Foreign Office with authentic information on neutrals' response to the war in Europe, and analyses the way Churchill used them. Turkey was seen by both sides to be the most important neutral power and therefore constitutes the case study for this analysis. The thesis answers the question ‘why did Turkey interest Churchill?’ by tracing his involvement with diplomatic intercepts back to 1914, and then revealing how the Government Code and Cipher School (GCCS) was empowered to continue monitoring such traffic until 1939, when 'Station X' was established at Bletchley Park (BP). Following two chapters that trace the interwar work of GCCS on the secret diplomatic traffic of most major powers and outline Turkey's place amongst those powers, the thesis concentrates on four events or processes in which Churchill's use of diplomatic messages played a part in determining his wartime policy, which was sometimes at odds with that of the Foreign Office. Chapter four answers the question what use did Churchill and the Foreign Office make of bjs to persuade Turkey to join the Allies between 1940 and 1942? Chapter five offers a new explanation of why the Adana conference of January 1943 produced little change in Turkish foreign policy. Chapter six explains the Dodecanese defeat of 1943 in the light of the signals intelligence Churchill was reading. Chapter seven shows the results at GCCS in London of the theft of secret Foreign Office papers in Ankara from November 1943: whether actual bjs were included in these papers; how they were received in Berlin and subsequently in Berne, Washington and London; and how they led to a breakthrough in reading the German diplomatic cipher, too late to be useful to Churchill. The thesis concludes by emphasising the personalised nature of wartime diplomacy and re iterates the reasons why Churchill and the Foreign Office attached such importance to their 'Most Secret Sources', though their availability to historians requires little change to the record. CONTENTS Prelims Introduction page 9 Chapter One - WHY TURKEY?........................................................... page 18 (i) Churchill and Turkey, 1914-15 (ii) Turkey in Context (iii) Churchill's Secret Source (iv) Churchill and Turkey, 1940-42 Chapter Two - CHURCHILL'S DIPLOMATIC INTERCEPTS page 37 (i) The 'Classical Cryptographers' (ii) Churchill's Intercepts: World War One (iii) Between the Wars (iv) Diplomatic Intercepts in the 1930s (v) GCCS's Interwar Achievements Chapter Three - BEFORE THE DELUGE: 1940-41 ............................page 53 (i) The Foreign Office and Turkey (ii) The Phoney War (iii) Germany Triumphant (iv) Different Views on Turkey (v) Churchill's Secret Intelligence, 1940-41 Chapter Four - CHURCHILL'S TURKISH APPROACH ................. page 72 (i) Churchill and Turkey, 1941-43 (ii) DIR/C On Stream (iii) Churchill's Turkey Hand: October - December 1941 (iv) Turkish neutrality and British Disasters, Spring 1942 (v) Turkish Friendship Sought Chapter Five - ADANA AND AFTER page 102 (i) The Road to Adana, January 1943 (ii) Why Churchill Failed (iii) Consequences: The Foreign Office and The Record Chapter Six - CHURCHILL’S ’ISLAND PRIZES LOST’ REVISITED page 132 (i) Preparations for the Dodecanese Assault (ii) The Dodecanese Assault and Counter-Assault (iii) Churchill Attempts Counter-Attack (iv) Diplomatic Consequences of Failure (v) Churchill and Turkey: November 1943 (vi) The Conferences Chapter Seven - CICERO, DULLES, PHILBY: THE MISSING DIPLOMATIC DECRYPTS................ page 158 (i) Introduction (ii) Historiography (iii) What Basna was Photographing (iv) How he did it (v) Berlin Assessments (vi) Washington Assessments (Venona) (vii) Whitehall Assessments Chapter Eight - CONCLUSIONS page 173 Appendices page 181 (i) DIR/C - HWl (Public Record Office) (ii) Prewar bjs (iii) Draft History of Room 40 OB by A. G. Denniston (iv) Wartime bjs HW3/162 (v) ’Y’ Programmes (Home Stations) June 1942 (vi) Diplomatic Venona in 1943 (vii) HW3 (Public Record Office) - GCCS in 1939 (viii) The Nazis’ use of Diplomatic Intercepts (ix) Berkeley Street Organisation Chart, 1943 (HW 3/3) (x) Who was Who Bibliography........................................................................................... page 208 (i) Primary Sources (ii) Secondary Sources ABBREVIATIONS AIR Air Ministry ADM Admiralty bj Secret signals intercept circulated in Whitehall in bluejackets BP Bletchley Park BSC British Security Co-ordination ' C ' General Sir Stewart Menzies, Head of the SIS CCC Churchill College, Cambridge C in C Commander in Chief CIOS Chief of the Imperial General Staff (Lord Alanbrooke) COS The (British) Chiefs of Staff C&W Cable and Wireless DEFE Files of the Minister of Defence (Churchill) at the PRO Dedip Foreign Diplomatic Decrypts DF Direction Finding DIR/C Churchill's Secret Intelligence Files DMI Director of Military Intelligence DNI Director of Naval Intelligence FO The (British) Foreign Office GCCS The Government Code and Cipher School GCHQ Government Communications Headquarters GHQ General Headquarters GPO General Post Office IWM The Imperial War Museum JIC Joint Intelligence Committee MEW Ministry of Economic Warfare MI IB MilitaryIntelligence (Cryptanalytical Section) MI6 Secret Intelligence Service (SIS) NAC National Archives of Canada (Ottawa) OKW High Command of the German Wehrmacht OTP One Time Pad PREM Prime Minister’s Office Papers (PRO) PRO Public Record Office RAF Royal Air Force SD Sicherheitsdienst - Intelligence Branch of the German SS sigint Signals Intelligence SIS Secret Intelligence Service (MI6) TA Traffle Analysis WO The (British) War Office WAT Wireless T elegraphy 7 I am after the Turk - Winston Churchill to Anthony Eden, 8 October 1942 PREM3/448 8 Dedication In memory of Alexander Guthrie Denniston 1881-1961 INTRODUCTION The literature on Churchill's use of secret intelligence at war is large and growing, in the USA as well as the UK. This thesis studies his use of diplomatic intercepts, based on newly discovered files Churchill himself hoarded during his lifetime. These files - which came to him almost daily from his intelligence chief Brigadier Stewart Menzies - contain a surprise, in that together with much Ultra traffic (high-grade or Enigma/Fish intercepts frequently referred to as 'Boniface'), there was much more diplomatic material in what Churchill was reading than any historian has hitherto realized. It was widely recognised, of course, that he studied the military, naval and air intercepts supplied to him from 1941. But it has only recently become apparent that Churchill's absorption in the product of the government's decyphering department had its origins in the First World War. In November 1914, when First Lord of the Admiralty, he had written the original charter for the legendary 'Room 40 OB', ensuring that German naval intercepts were available to his nominees. This involvement with, and possessiveness over, secret signals intelligence continued unabated until 1945 when Japanese diplomatic messages between Berlin and Tokyo informed the war leadership that the time had come to drop atomic bombs on Hiroshima and Nagasaki. The intercepted telegrams he studied were diplomatic as often as army and navy traffic in and between both world wars. Churchill had always been interested in Turkey, ever since intercepts supplied to him by the Director of Naval Intelligence, Admiral Reginald Hall, told him he could have secured Turkish non-participation in hostilities in February 1915 and he chose to disregard this vital information. Later he backed a Greek foray against the Turks at Smyrna in 1922 in an episode in which intercepted diplomatic messages between the Turkish ambassador in Paris and Constantinople provided him, Curzon and Lloyd George with vital information on the attitude of the Turkish leadership. By 1940 he had convinced himself that he alone could bring Turkey into the war as an ally. Few people, then or now, agreed with him, but he took immense pains to develop British policy towards Turkey in a manner that would shorten the