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Room 40’s brilliant World War I codebreakers


Even in the early morning gloom and wrapped in a heavy overcoat, Ted Palmer recognised the man who came in out of the London rain for his first day’s work at a new office as a ‘Parisian dresser’, and, at least by repute, already established as his department’s most ‘active, intelligent, enterprising, brilliantly deductive brain’ – which meant, ‘more properly, a true Sherlock Holmes.’

Palmer eagerly shook his colleague’s hand and welcomed him inside to the sparsely furnished upstairs corner room where he would spend much of the next three years. It was 6 September 1914, and some 400 miles away a million Allied soldiers were then in the process of desperately pushing their shoulders against a front line being battered by the advancing German army on the outskirts of Paris. 

Palmer himself was a Welsh research physicist attached to the British Admiralty, and more particularly to OB (Old Building) 40, the cryptography department concerned with cracking German military and diplomatic codes. Sometimes called ‘Room 40’, in reality it was a maze of interconnecting ‘cubby-holes, dens, and barrack-like typing pools’ of various shapes and sizes, and at peak capacity it employed some 800 wireless operators and ninety cryptographers and other specialists. In February 1917 the boffins of Room 40 were to play a significant role in influencing the final outcome of the war when they successfully decoded the ‘Zimmerman Telegram’ in which the German government had sought to encourage Mexico to attack the United States, a key moment in US president Woodrow Wilson’s decision to enter hostilities on the Allied side.

The ‘Sherlock Holmes’ figure emerging out of the Whitehall rain that September morning was 59-year-old (James) Alfred Ewing, a silver-haired Scot who had served as the first Professor of Engineering at University College in his native Dundee before going on to take up an academic post in Cambridge, and, in April 1903, to join the Admiralty in the newly created role of Director of Naval Intelligence (DNE) at Greenwich. It was said of Ewing that he was ‘careful at all times of his appearance, his suits were mostly grey, added to which he generally wore – whatever the fashion – a white pique stripe to his waistcoat, a mauve shirt, a white butterfly collar and a dark blue bow tie with white spots.’ To this ensemble, the newly arrived DNE sometimes added an ivory-topped walking stick, which he would occasionally jab towards a surprised colleague’s nose for additional conversational emphasis.

Physically, Ewing was something of a macaw in the rookery of British naval intelligence. Professionally, he was probably the most eminent of the various intellectuals and academics to pass through Room 40 during the course of the First World War, a list that also included a ‘siren-voiced’ Presbyterian minister and biblical authority-turned-codebreaker named Revd. William Montgomery; Nigel de Grey, an Eton-educated book editor so mild mannered he was affectionately known as ‘the door mouse’, but who liked nothing more than to casually deconstruct seemingly impossible ciphers for his own amusement; Dillwyn ‘Dilly’ Knox, a classics scholar and papyrologist who absent-mindedly forgot to invite two of his own brothers to his wedding, and who was later said to have done some of his best wartime work while lying in the bathtub he had installed in his Admiralty office; and Alastair Denniston, a former Scottish Olympic field-hockey player and world-renowned expert on German literature who would still be working as a British intelligence analyst in the Second World War.  

Presiding over this group from November 1914, and matching them all for personal idiosyncrasy was 44-year-old Captain (later Admiral) Reginald Hall, known as ‘Blinker’ due to a pronounced facial twitch said to have caused one of his eyes to ‘flash like a Navy signal lamp’, a trait he combined with a penetrating stare, luxuriantly bushy eyebrows, conspicuously false teeth, and, according to the US ambassador to London in a cable home to President Wilson, ‘An intellect that [made] him the one genius the war has developed … Neither in fiction nor in fact can you find any such man to match him.’ The Government Code School established at Bletchley Park in August 1939 was the direct successor of this team of brilliant and often eccentric civilian scholars, lawyers, publishers, schoolteachers and theologians assembled twenty-five years earlier at the Admiralty Building in Whitehall.

Some time on or around 30 January 1917, Room 40’s William Montgomery and Nigel de Grey successfully decoded the secret message sent by the German Foreign Minister Arthur Zimmerman to his ambassador in Mexico. ‘Blinker’ Hall had to proceed with some care in exploiting this breakthrough, taking care to bring the telegram to Washington’s attention without letting slip that Room 40 was in a position to read the enemy’s diplomatic traffic. As a result, it would not be until 22 February that Hall shared the contents of the cable with the American embassy in London. From there a copy of the deciphered text made its way to the US Secretary of State, and then on to President Wilson. Wilson, who was not a man given to public displays of emotion, exclaimed ‘Good God!’ several times as he read it at his White House desk on 1 March.  Just five weeks later, the United States declared war on Germany. As Winston Churchill wrote: ‘A new Titan long sunk in doubt now arose [and] began to arm … The end was finally in sight.’

By Christopher Sandford

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