Stewart Menzies Major General Sir Stewart Graham Menzies , ( ; 30 January 1890 – 29 May 1968 ) was Chief of MI6 ( SIS ) , British Secret Intelligence Service , during and after the Second World War . Early life , family . Stewart Graham Menzies was born in London into an immensely wealthy family , as the second son of John Graham Menzies and Susannah West Wilson , daughter of Arthur Wilson of Tranby Croft . His grandfather , Graham Menzies , was a whisky distiller who helped establish a cartel and made huge profits . His parents became friends of King Edward VII who at the time was rumoured to be Menzies ' father , though this was probably not the case . Menzies was a nephew of Robert Stewart Menzies . But Menzies ' father was dissolute , never established a worthwhile career , and wasted his share of the family fortune ; he died of tuberculosis in 1911 in his early 50s , leaving only a minimal estate . Menzies was educated at Eton College , becoming president of the student society Pop , and graduating in 1909 . His achievements were in sports , he excelled at hunting and cross country running ; and he was also an excellent student . Early military career . Joins Life Guards . From Eton he joined the Grenadier Guards as a Second Lieutenant . After a year with this regiment , he transferred to the Second Life Guards ( British Army ) . He was promoted to Lieutenant and appointed Adjutant by 1913 . First World War combat . During the First World War Menzies served in France . He was wounded at Zandvoorde in October 1914 , and fought gallantly in the First Battle of Ypres , November 1914 . Menzies was promoted to captain on 14 November , and received the DSO in person from King George V on 2 December . Enters intelligence service . Menzies ' regiment was decimated during fighting in 1915 , suffering very heavy casualties in the Second Battle of Ypres . Menzies was seriously injured in a gas attack in 1915 , and was honorably discharged from active combat service . He then joined the counterintelligence section of Field Marshal Douglas Haig , the British commander . In late 1917 he reported to high British leadership that Haig ' s intelligence chief Brigadier John Charteris was fudging intelligence estimates , which soon led to Charteris ' removal . This whistle - blowing was apparently done very discreetly . Menzies was promoted to brevet major before the end of the war . Joins MI6 . Following the end of the war , Menzies entered MI6 ( also known as SIS ) . He was a member of the British delegation to the 1919 Versailles Peace Conference . Soon after the war , Menzies was promoted to lieutenant - colonel of the Imperial General Staff , General Staff Officer , first grade . Within MI6 , he became assistant director for special intelligence . Admiral Hugh Sinclair became director - general of MI6 in 1924 , and he made Menzies his deputy by 1929 , with Menzies being promoted to full colonel soon afterwards . In 1924 , Menzies was allegedly involved — alongside Sidney Reilly and Desmond Morton — in the forging of " The Zinoviev Letter " . This forgery is considered to have been instrumental in the Conservative Party ' s victory in the United Kingdom general election of 1924 , which ended the country ' s first Labour government . Becomes Chief of MI6 . In 1939 , when Admiral Sinclair died , Menzies was appointed Chief of SIS . He expanded wartime intelligence and counterintelligence departments and supervised codebreaking efforts at Bletchley Park . Before the Second World War , the SIS had been a relatively minor and uninfluential branch of the British government ; budgetary pressures after the First World War and during the 1930s of the Great Depression were the main reasons for this . Oversees codebreaking . When the Second World War began , SIS expanded greatly . Menzies insisted on wartime control of codebreaking , and this gave him immense power and influence , which he used judiciously . By distributing the Ultra material collected by the Government Code & Cypher School , for the first time , MI6 became an important branch of the government . Extensive breaches of Nazi Enigma signals gave Menzies and his team enormous insight into Adolf Hitler ' s strategy , and this was kept a closely held secret , not only during the war , but until as late as 1974 . Frederick Winterbotham ' s 1974 book " The Ultra Secret " lifted the cloak of secrecy at last . The Nazis had suspicions , but believed Enigma to be unbreakable , and never knew during the war that the Allies were reading a high proportion of their wireless traffic . Menzies kept Prime Minister Churchill supplied daily with important Ultra decrypts , and the two worked together to ensure that financial resources were devoted towards research and upgrading technology at Bletchley Park , to keep pace with Nazi coding refinements , as well as directing talented workers to the massive effort , which employed nearly 10 , 000 workers by 1945 . Bletchley ' s efforts were decisive in the battle against Nazi submarine warfare , which was severely threatening trans - Atlantic shipping , particularly in the first half of 1943 . Britain , which was cut off from Europe after mid - 1940 , was almost completely dependent on North American supplies for survival . The access to Ultra was also vitally important in the battle for Normandy , leading up to D - Day in June 1944 , and afterwards . Menzies has been suspected as being involved with the assassination of François Darlan , the Vichy military commander who defected to the allies in Algeria . British historian David Raynolds noted in his book , " In Command of History " , that Menzies - who rarely left London during the war - was in Algiers around the period he was killed , making SOE involvement seem likely . Furthermore , Darlan ' s assassin , La Chapelle , had been a member of the resistance group led by Henri d ' Astier . Menzies , who was promoted to major - general in January 1944 , also supported efforts to contact anti - Nazi resistance , including Wilhelm Canaris , the anti - Nazi head of Abwehr , in Germany . Prime Minister Winston Churchill was kept informed of these efforts throughout the war , and information from and about the Nazi resistance was exploited tactically . Menzies coordinated his operations with SOE ( although he reputedly considered them " amateurs " ) , BSC , OSS and the Free French Forces . After the Second World War . After the war , Menzies reorganised the SIS for the Cold War . He absorbed most of SOE . He was sometimes at odds with the Labour governments . He also had to weather a scandal inside SIS after revelations that SIS officer Kim Philby was actually a Soviet spy , although this came after Menzies had retired . After 43 continuous years of service in the British Army , Menzies retired to Bridges Court in Luckington in rural Wiltshire at 62 in mid - 1952 . Menzies was certainly adept at bureaucratic intrigue , a virtual necessity in his position , but his efforts as ' C ' had a major role in winning the Second World War , as evidenced by his nearly 1 , 500 meetings with Prime Minister Churchill during the war . Marriages . His first marriage was in 1918 to Lady Avice Ela Muriel Sackville , younger daughter of Gilbert Sackville , 8th Earl De La Warr and Lady Muriel Agnes Brassey , daughter of Thomas Brassey , 1st Earl Brassey . They were divorced in 1931 , when she left him for another man . His second wife Pamela Thetis Beckett ( d . 13 March 1951 ) , fourth daughter of the Honourable Rupert Evelyn Beckett by his wife Muriel Helen Florence Paget , daughter of Lord Berkeley Charles Sydney Paget , himself a younger son of the 2nd Marquess of Anglesey , whom he married in 13 December 1932 , was an invalid for many years , suffering from clinical depression and anorexia nervosa , but she bore him his only child , a daughter , Fiona , in 1934 . His third marriage was in 1952 ( as her fourth husband ) to Audrey Clara Lilian Latham ( b . 1899 ) , formerly wife of Sir Henry Birkin , 2nd Bt . ( and two other men ) , and daughter of Sir Thomas Paul Latham , 1st Bt . . Stewart and Audrey were both over age 50 at the time of their marriage , each had separate estates ( his in Wiltshire , west of London , hers in Essex , east of London ) , and they for the most part lived separately , but they met in London for dinner each Wednesday . By his third marriage , he had two stepdaughters Pamela Buxton ( later wife of Lord Buxton of Alsa ) and Sara Hanbury . Anthony Cave Brown also reports that Menzies had a long - standing affair with one of his secretaries , which he ended upon retirement ( and presumably re - marriage ) in 1952 ; the secretary apparently tried to kill herself at that time . Menzies died 29 May 1968 .