Dilly

by Batey, Mavis;

  However, official attitudes to the possibility of breaking the enemy’s coded signals changed after the German light cruiser Magdeburg was wrecked in the Baltic and the Russians captured two codebooks, one of which was duly delivered to the First Lord of the Admiralty, Winston Churchill, on 13 October 1914. Churchill was over the moon and, with some poetic licence, wrote the incident up in his The World Crisis in 1923, telling how he had personally received the precious Signalbuch der Kaiserlichen Marine (SKM) – the Signal Book of the Imperial Navy – a high-level ‘flag code’. According to Churchill the ‘sea-stained’ codebook had been found on a German officer, ‘clasped in his bosom by arms rigid in death’. It would not be long before Ewing received another maritime codebook, captured by the Australians from a merchant ship off Melbourne; this was the Handelsverkehrbuch (HVB) – merchant navy traffic book – used by the German Admiralty and warships for communication with merchantmen. The third stroke of luck would come when a British trawler in the Heligoland Bight found in its nets a lead-lined chest from a sunken German vessel containing a copy of the Verkehrsbuch (VB) – traffic book, the codebook used for routine message traffic. The delighted codebreakers called it ‘The Miraculous Draught of Fishes’ and Room 40 now had enough material to begin codebreaking in real earnest. There was then no copying gear available and as there was only one copy of the important SKM codebook, Russell Clarke turned himself into a photographer and laboured at home to produce three additional copies.

  New premises were found in Room 40 of the Old Admiralty Buildings by the newly appointed DID in October. Captain Reginald ‘Blinker’ Hall was a much more dynamic leader than his predecessor, Admiral Oliver, and greatly improved the status of what was by now dubbed ‘special intelligence’. Churchill then drafted in his own hand a charter for Room 40; it was headed ‘Exclusively Secret’ and called for a study of ‘all the intercepts, not only current but past, and to compare them continually with what actually took place in order to penetrate the German mind and movements’. He expressed the wish that Ewing would ‘associate himself continuously’ with this work. A search would be made for what later became known as ‘professor types’. However, this did not happen overnight, as although the Room 40 codebreakers had shown that they were capable of dealing with the messages encoded from the German navy codebooks, they had yet to convince some of the Admiralty’s sea lords that the intelligence derived from the signals would be of any use to them.

  Their Lordships were soon shocked into recognition of the value of special intelligence, when, on 14 December 1914, they received information from Room 40 of a planned bombardment by German vessels, possibly on towns along Britain’s eastern coast. These towns proved to be Hartlepool, Whitby and Scarborough, but the navy was unable to get its act together in time to prevent the disaster. Churchill wrote in The World Crisis:

  Although the bombarded towns, in which nearly 500 civilians had been killed or wounded, supported their ordeal with fortitude, dissatisfaction was widespread. However, we could not say a word in explanation. We had to bear in silence the censure of our countrymen. We could never admit for fear of compromising our secret information where our squadrons were or how near German raiding cruisers had been to their destruction. One comfort we had. The information on which we had acted had been confirmed by events. The sources of information on which we relied were evidently trustworthy.

  Trustworthy indeed! Room 40 was in business, and matters were very different when the Admiralty received information from Room 40 on 23 January 1915 that there was to be a second attack, with battle cruisers assembling at Dogger Bank. This time the navy was ready for them and inflicted considerable damage. Churchill was up at dawn on the next day with Admiral Fisher, when at 8 a.m. came the news that the enemy had been sighted. Churchill recalled in 1923, as though it were yesterday, the excitement and the tension in Room 40 as he watched the codebreakers at work on the Magdeburg’s SKM codebook. The codebook had an accompanying grid chart for latitude and longitude, which made even routine messages important, since it allowed instructions about a ship’s destination to be plotted. Churchill said:

  There can be few purely mental experiences more charged with cold excitement than to follow, almost from minute to minute, the phases of a great naval action from the silent rooms of the Admiralty. Out on blue water in the fighting ships amid the stunning detonations of the cannonade, fractions of the event unfold themselves to the corporeal ear. There is the sense of action at its highest; there is the wrath of battle; there is the intense self-effacing, physical or mental toil. But in Whitehall only the clock ticks and quiet men enter with quick steps, laying strips of pencilled paper before other men, equally silent, who draw lines, and scribble calculations and point the finger or make brief subdued comments. Telegram succeeds telegram at a few minutes’ interval as they are picked up and decoded, often in the wrong sequence, frequently of dubious import; and out of these a picture always flickering and changing, rises in the mind, and imagination strikes out around it at every stage flashes of hopes and fears.

  Churchill was clearly hooked on special intelligence and laid down instructions for three copies of the message translations to be made, one for the chief of staff and his Operations Division, one for the DID and one to be retained in Room 40. He insisted during his two years in office that this should be done by ‘logging’ in true minute-by-minute ship’s log style, which Room 40 always regarded as a useless burden. Denniston recalled wryly in his memoirs:

  The Log became an object of hatred before long. The First Lord had called into being that particular kind of filing the current work and it was over two years when its originator was elsewhere, before a more labour-saving and less soul-destroying method was allowed to replace it. In the days when the watchkeeper averaged 12 messages it could be written up, though even then it was the fashion to let the messages accumulate and allow the new watch to write up the log and thus appreciate the situation. But it was beyond a joke when naval action was pending or Zepps [Zeppelin airships] fluttering and the watchkeeper had 12 to 20 pages of the book to write up.

  Churchill’s authority to increase the staff was another matter and when it came to intellectual capacity, Ewing naturally turned his attention to his old college, where he had already tentatively approached King’s lay dean, the ancient historian Frank Adcock, the historian Frank Birch and the classical scholar Dilly Knox, who in addition to their research skills had the right ‘ivory tower’ approach that would allow them to focus exclusively on one subject and would be ideal for their secret work. Dilly was the first ‘Kingsman’ to find his way through the arches of the Admiralty Old Buildings early in 1915 to join Churchill’s quiet men in Room 40, and it was not long before he would prove his skill as a codebreaker. Although Ewing was still nominally in charge of Room 40, when Dilly arrived at the beginning of 1915, in the aftermath of the Dogger Bank excitement, it was coming increasingly under ‘Blinker’ Hall’s control, as Ewing had other activities to deal with, and it was Hall’s name which in future would be associated with Room 40.

  William Reginald Hall went to sea as a midshipman in 1884, aged fourteen, and became a commander in 1901, reaching the pinnacle of his sea-going career in 1913, when he was appointed commander of the new battle cruiser Queen Mary. He saw action at the Battle of the Heligoland Bight in 1914 before being recalled, by ill health, to the Admiralty to become DID, in place of Admiral Oliver. He was nicknamed ‘Blinker’ because of his frequent blinking mannerism. As well as supervising special intelligence, he operated as spymaster in traditional cloak-and-dagger work, which, like Churchill, he saw patriotically as part of Kim’s ‘Great Game’, immortalised by Kipling.

  Room 40’s codebreakers were somewhat of a trial, as they never took to naval terminology and often failed to keep the right watches. However, just before Dilly arrived ‘Blinker’ Hall had had the good sense to appoint a real navy man to take charge, Commander (later Admiral) Herbert Hope, who would analyse the messages being broken
every day by Room 40 and correct pitfalls, such as in one decoded German naval message, which had annoyed the Admiralty: ‘One of our torpedo boats will be running out into square 7F at 8 p.m.’ Ships do not ‘run out’, their Lordships complained, they ‘proceed’. Hope knew little German and no codebreaking, but William ‘Nobby’ Clarke, another barrister, who worked under him, is on record as saying in a post-war archive account, ‘Narrative of Captain Hope’, that in spite of this ‘his consummate seamanship and ability to read the enemy’s mind made his election a stroke of genius’. Although ‘Blinker’ had had little experience of ‘professor types’, he admired their skills, but he wanted to widen the scope of Room 40’s expertise. He brought in two personal assistants, Claud Serocold, a stockbroker, and Lord Herschell, a government whip in the House of Lords, plus ‘Nobby’ Clarke, and Nigel de Grey from the publishers Heinemann, who would soon prove an excellent choice.

  Hall prided himself on finding the right slot for each of their different talents and capabilities and was a past master at delegation. In his biography, he wrote:

  A Director of Intelligence who attempts to keep himself informed about every detail of the work being done cannot hope to succeed: but if he so arranges his organisation that he knows at once to which of his colleagues he must go for the information he requires, then he may expect good results. Such a system, moreover, has the inestimable advantage of bringing out the best of everyone working under it, for the head will not suggest every move: he will welcome and, indeed, insist on ideas from his staff. And so it was, from first to last, in the Intelligence Division.

  This was the advice he passed on to Rear-Admiral John Godfrey, the Second World War director of Naval Intelligence, when Godfrey was reorganising the Naval Intelligence Division in 1939 in preparation for the war.

  Dilly was immediately put onto the small team dealing with codes and cipher keys. Messages were sent in groups of letters or figures. The operator would look up the relevant code-group for each word or figure in the message in a codebook. This would include code-groups that represented much-used terms such as ‘Musterung auf der Gefechtsstation’ – muster at battle stations – and common syllables, so that unusual words which did not appear in the codebook could be encoded. Only low-grade messages such as weather reports were encoded directly from the codebooks; the code-groups for high-grade naval messages were given added security using a cipher. Simply put, codes replace single words, figures or phrases with a single code-group, while a cipher replaces each individual letter or figure with another letter or figure. Encoding the messages to form code-groups, which were then enciphered, in a process which came to be known as super-encipherment, was designed to make them harder for the British to break. The settings of a cipher are known as the ‘key’ in English or to the Germans as the ‘Chi’, from the French chiffre. Room 40 referred to breaking these enciphered messages as solving the key. At the beginning of the war, the main key remained the same for three months, which gave the Room 40 codebreakers a good start in familiarising themselves with the message characteristics that provided the ‘cribs’ for key changes – pieces of known text that could be predicted to be used in certain situations and would therefore give the codebreakers a ‘way in’ to the cipher and the code that lay underneath it. At the beginning of 1915, when the key was changed, the messages began with an enciphered serial number, so that it was easy enough to see when a message was out of order and a change had occurred; it would then provide a way in to the new encipherment tables, which would not have been possible if the operators had given the serial number in clear.

  It was Fleet Paymaster Charles Rotter, the principal expert on the Kaiser’s navy in the Naval Intelligence Division, who had first understood that having the SKM codebook from the Magdeburg was not the end of the story, as there was a further process of encipherment to contend with. Dilly soon became involved in solving the first new Chi imposed on the SKM codebook soon after the Dogger Bank success. The cipher proved to be a letter-for-letter substitution where a vowel was replaced by a vowel in order to keep the code-group pronounceable. Churchill always felt that he was in on anything to do with signals intelligence derived from using the Magdeburg’s codebook and immediately came in to congratulate Room 40 when he heard the overlying key to the SKM code-groups had been broken.

  Dilly had taken to the deciphering side of signals intelligence like a duck to water and was the only member of Room 40 who had any experience of basic codebreaking, since similar attitudes and thought processes were needed for solving unreadable scripts and decoding messages. Both required inspired guesswork and this was Dilly’s forte. Most of the other new recruits were fluent in German and were put to work on translating the decoded messages and analysing them, like Rev. William Montgomery, an authority on early church fathers, who had translated many German theological works and had been working in the censorship department. Dilly was obviously a godsend. He had not had much to do with secret writing, where the text is intentionally made unintelligible through encipherment, as he had dealt mainly with fragmented and damaged texts of literary papyri, which needed expert knowledge of the ancient language to unravel, but he must have been in his element when Room 40 received the charred remains of a codebook from a shot-down Zeppelin.

  Dilly was also familiar with emblematic hieroglyphs, which served him well in attempting to reconstruct the ‘telegraphese’ in the German navy codebooks. This type of codebook had been in use for some time by commercial firms; provided you knew you were dealing with one for an oil company, say, the associated words of barrels and orders in the message were soon isolated and the repeated words guessed. A codebook needed two columns to serve sender and recipient in respective alphabetical or numerical order.

  A new secret codebook would take a long time to compile but having the three naval books SKM, HVB and VB in its possession gave Room 40 a head start. Dilly had spent much time identifying the idiosyncrasies of Greek copyists on literary papyri and was well aware of how they made errors, so he was prepared for Morse operators making mistakes in the messages. He was also prepared for lazy operators taking short cuts in encoding telegrams, knowing this would provide a way in for him. A real bonus for Room 40 would be finding complete messages that had been decoded in one of the easy weather codes then repeated in the more difficult messages that had also been enciphered, giving the codebreakers the key to the cipher. Such repeated messages were the Rosetta stone of codebreaking and were later called ‘kisses’ at Bletchley Park as anybody who spotted one marked it XX.

  Room 40’s big moment would come at the beginning of 1916, when the first major encounter with the German High Fleet was being planned, which finally took place on 31 May. It is best described by Winston Churchill in The World Crisis, as Room 40’s successes moved on from the Dogger Bank to Jutland:

  Earlier in this account, I recorded the events which secured for the Admiralty the incomparable advantage of reading the plans and orders of the enemy before they were executed. Without the codebreakers’ department there would have been no Battle of Jutland. But for that department the whole course of the naval war would have been different. The British Fleet could not have remained continuously at sea without wearing down its men and machinery. If it had remained almost continuously at sea the Germans would have been able to bombard two or three times a month all our East Coast towns.

  Speaking of the Magdeburg’s codebook as the triumph of signals intelligence, he continued:

  These signal books and the charts associated with them were subjected to a study in Whitehall in which self-effacing industry and imaginative genius reached their highest degree … By the aid of these books and the deduction drawn from their use, the Admiralty acquired the power of reading a proportion of the German wireless messages … capable of presenting to the Fleet a stream of valuable information.

  Dilly was heavily involved and, like the other members of the team, frequently worked throughout the night on such messages with the windows b
lacked out against Zeppelin raids; by this time the key was changed every day at midnight and there was a rush to solve it before the morning. He managed to get his brother Ronnie recruited to join him and, as one of the codebreakers put it, a figure ‘in clerical garb’ now appeared in the Admiralty’s Room 40. Ronnie mentioned mildly to one of the family that Dilly had never explained to him exactly what he was meant to be doing. As I was to discover myself, Dilly was never very good at explaining, always believing that people would rather work it out for themselves, as Ronnie did. After a short while, when the emergency was over, he was transferred to a branch of the War Office known as MI7, which studied the newspapers of neutral countries in order to trace the effect of enemy propaganda.

  The Battle of Jutland under Admiral John Jellicoe was memorable as being the only occasion in the First World War when the rival fleets met and, although the outcome of the battle was not decisive, it left the British fleet the undisputed master of the seas. The undoubted important contribution made by signals intelligence led directly to administrative changes in Room 40. ‘Nobby’ Clarke, who was on duty analysing the traffic throughout the battle, recorded that the codebreakers had provided advance information about the exact composition of the German fleet and its movements through studying call-signs, transits in the Kiel canal and exercises in the Baltic, even before decoding the messages, but that the Operations Division had failed to make use of the information.