Secret Warriors

by Taylor Downing

  After the Somme, the Germans introduced the Albatros DI, and the pendulum swung again, this time in their favour. Powered by a 160 hp Mercedes engine, the Albatros could fly at up to 110 mph and with twin Spandau machine guns could fire 1600 rounds a minute. When the ground fighting resumed at the battle of Arras in the spring of 1917, the RFC no longer enjoyed aerial supremacy but still had to carry on performing the daily rounds of reconnaissance and artillery spotting. During April 1917 the RFC lost 250 aircraft shot down and 400 airmen killed or wounded. The month became known as ‘Bloody April’.25

  A new set of aircraft names now became the fighting champions of their day. The Germans had their Fokker biplanes and triplanes, the British responded with Bristols, Vickers and Nieuports. The Germans then employed Albatroses, while the RFC introduced first the Sopwith Pup and then the Camel, which once again brought them mastery of the skies. The new generation of aerial warriors attracted much popular attention, but for most pilots on both sides, their flying careers on the Western Front proved tragically short – the average life expectancy of a young flyer in the RFC in early 1917 was just two weeks.26

  On 1 April 1918 the RFC and the Royal Naval Air Service were merged to form a new military service, the Royal Air Force. But its creation came at a time of crisis on the Western Front, to which the Germans had transferred huge numbers of troops from the Eastern Front after Russia dropped out of the war following its revolution in 1917. The Germans, though, were now wary of giving too much away to aerial observation, a concern which percolated right up to the German commander. General Ludendorff sent a memo warning of the ‘constant observation of our organisation by the enemy’s aeroplanes in trench warfare and the technical improvements introduced in aerial photography’. Ludendorff instructed his commanders to ‘hide our artillery positions from air observation’ and to make ‘greater endeavours than in the past’ with ‘camouflage work’. He went on, ‘The plates employed for photography from great heights are extraordinarily sensitive to colours and show up clearly the slightest differences in shades, even those imperceptible on the ground.’27

  Ludendorff’s instructions were a great tribute to the success of Allied photo intelligence. Despite the German camouflage, throughout February 1918 British reconnaissance patrols had picked up the movement of large numbers of troops, the building of new supply dumps and the construction of eighteen new airfields. The Allied flyers were able to predict that a major offensive was imminent, even if they did not know where and when it would come.

  On 21 March 1918, the Germans launched their anticipated attack and threw the French and British armies reeling back. The offensive began during a period of foggy weather when aerial reconnaissance was impossible and so the location of the attack, along the Somme, came as a complete surprise to the Allies. Within a few weeks the British Army had lost more than 100,000 men, surrendering much territory captured so painfully over the last two years, and by the second week of April the British commander-in-chief, Sir Douglas Haig, viewed the situation as highly perilous. His famous Order of the Day on 11 April concluded with the words, ‘With our backs to the wall and believing in the justice of our cause each one of us must fight to the end.’28 Then, on the following day, the weather cleared and RAF reconnaissance aircraft brought back for the first time detailed and accurate information about the German positions. More photographs were taken that day than on any other since the beginning of the war. Using the intelligence they picked up from these photos, the Allies could again bomb and shell German positions with accuracy. Haig noted in his diary the ‘satisfactory results of today’s work in the air’.29

  The German offensive rolled forwards for another three months but slowly began to run out of steam. And when the Allies launched their counter-offensive in July, aerial photographs had already delivered to the Allied commanders detailed outlines of the German positions. Furthermore, having destroyed so many German aircraft the Allies now enjoyed total air supremacy, and British and French aircraft were able to fly up to eighty miles behind the German front line to report on the movement of reinforcements by train. American aircraft too were now arriving in large numbers; by the summer of 1918 there were forty-five American squadrons and twenty-one Photographic Sections on the Western Front. When it came to aerial observation and photo interpretation, the Americans lined up to learn the new science from the French, who had led many of the innovations in the war years.

  The Allied offensive combined rolling artillery bombardments ahead of advancing infantry, with huge numbers of tanks supported by ground attacks from RAF aircraft that were closely integrated into the battle plan. The static war of the last four years became a mobile war once again and aerial photography was used to record the German withdrawal across France and Belgium until the German high command finally agreed to an armistice in November. By the final campaigns of the war, photo intelligence had unquestionably come of age. In the course of 1918 over ten million aerial photographs were delivered to the armies in Belgium and France.30

  The First World War had not entirely been fought on the Western Front. A hugely successful campaign was conducted in Palestine during 1917–18, when General Allenby led a combined army from Egypt across the Sinai to defeat the Ottoman Turks at Gaza before advancing north to capture Jerusalem. He seized all of Palestine from the Turks and by the end of the war had advanced as far as Damascus. Allenby’s armies had received support on the east of the Jordan river from the Arabs, who had risen in revolt against the Turks and, encouraged by Colonel T.E. Lawrence ‘of Arabia’, had advanced along the right flank of Allenby’s army.

  Much of the area over which these Allied armies marched had never been properly mapped, but Lieutenant Hugh Hamshaw-Thomas of the RFC was to change all that. Hamshaw-Thomas had been a leading palaeo-botanist before the war, well known for his study of fossils, and was a Fellow of Downing College, Cambridge. He was a quiet, unassuming and studious young man whose painstaking approach to the study of Jurassic fossils was now brought to bear on aerial photography. From late 1916 he led an aerial reconnaissance unit in Egypt that produced huge photo mosaics. The detailed maps produced from these mosaics covered more than 500 square miles of Egypt, Palestine and Syria and made a significant contribution to the success of the advancing armies moving into territory that had been controlled by the Ottomans for centuries.31 Hamshaw-Thomas’s work demonstrated yet again the importance of aerial photography to military intelligence.

  By the end of the war, enormous strides had been made in the science of aerial reconnaissance. Cameras with long lenses manufactured in the newly created British optical industry could produce detailed images of vast areas from as high as 20,000 feet, while flexible roll film had begun to replace fragile glass plates. At the same time, the process of interpreting information from these photographs and of producing detailed maps of up to about 1:20,000 scale had been perfected. Photo intelligence had become the principal source of understanding where the enemy was located, how he was moving his reserves and what he was likely to do next. As the artillery’s long-range guns had become the major aggressive weapon of the war, so they too had used aerial reconnaissance to sustain their weapons’ accuracy and deadly effect.

  It’s fair to say that the twentieth-century battlefield had been reinvented by the use of photo intelligence. The foundations had moreover been laid for aerial mapping to chart great swathes of the globe in the 1920s and 1930s. In the Middle East aerial photographs would be used to map geological patterns and to decide where best to dig for oil. In both North and South America and in Australia it became possible to survey huge tracts of land from the air. An entirely new science had thus come out of the war. But aerial reconnaissance and photo interpretation were not the only forms of intelligence to be transformed in the laboratory of war from 1914 to 1918.

  Part Two

  Code Breakers

  5

  Room 40

  On the first day of war, 5 August 1914, only a few hours after the cable shi
p Alert had severed the telegraph cables linking Germany with the outside world, the director of the Intelligence Division of the Admiralty, Rear Admiral Henry Francis Oliver, was walking across Horse Guards Parade towards his club in Pall Mall for lunch when he met his friend and colleague Sir Alfred Ewing, the director of Naval Education. Oliver asked Ewing to join him, as he had a problem he thought Ewing might be able to help him with. For some days he had been receiving in his capacity as head of intelligence intercepted cables that appeared to be German naval signals. But they were in some sort of code and meant nothing to Oliver. However, he knew that Ewing had an interest in ciphers, since the pair had a few months before discussed ‘a rather futile ciphering mechanism’. Over lunch, Oliver said he was looking for someone to try to decipher the signals, which would no doubt grow in number over the next few months. As naval education was likely to be put on hold until the war had been won, Oliver suggested that Ewing might like to run this small section for him. Ewing promptly agreed.1

  Sir Alfred Ewing was at the time fifty-nine years of age. A short, thickset Scot with bright blue eyes beneath shaggy eyebrows, he had a quiet voice with a mild Scottish accent and always dressed immaculately regardless of the fashion in a grey suit with a striped waistcoat, a mauve shirt and a dark blue bow tie with white spots.2 The son of a Scottish clergyman, he had won an engineering scholarship to Edinburgh University and spent some years with cable firms working on engineering research, including such varied subjects as magnetism and Japanese earthquakes. He returned to the academic world at Dundee University in his early thirties and was appointed Professor of Mechanical Engineering at Cambridge in 1890. Five years later he received the Gold Medal of the Royal Society for his work on magnetic induction. In the reforms of the Royal Navy in the early years of the twentieth century, the First Sea Lord, Jacky Fisher, persuaded him to take up a new position in the navy and become Director of Education. He made a great success of this and was knighted in 1911. His hugely successful career had made him one of the nation’s leading scientists and he would go on to become President of the British Association for the Advancement of Science.

  Ewing now turned to the world of codes and ciphers, a subject in which he was interested but about which he freely admitted he was grossly ill-informed. Taking a scholarly approach, he first visited Lloyds the insurers and the General Post Office to study their code books. He then spent some time in the stacks of the British Museum examining old, dusty books on code making. With more and more intercepted signals flooding in to the Admiralty, up to one hundred a day, it was evident that Ewing would need assistance, so he turned to what could best be described as the Royal Navy’s ‘old boy network’. Knowing they would have the necessary qualities of discretion for such top secret work, he asked some of the teachers in the naval colleges at Osborne and Dartmouth, men he knew and trusted, to join him.

  One of these was Alexander Denniston. Thirty-three years old, Denniston was another quietly spoken Scotsman. A great sportsman who had played hockey in the Olympic Games held in London in 1908, he had one of the great skills now needed in Ewing’s team. He was a brilliant linguist, had studied at the Sorbonne and the University of Bonn and was a fluent German speaker. Thinking the assignment to the Admiralty would be a short one as the war was likely to be over in a couple of months, Denniston agreed to join Ewing. He was eventually to retire from the world of code breaking only in 1942.

  Ewing, Denniston and a few others recruited at the same time were the first official code breakers specifically employed to crack coded messages sent by the German navy and by German diplomats abroad. Given the prevailing strong sense that studying the enemy’s signals was a rather ‘un-gentlemanly kind of activity’, they were all sworn to secrecy.3 They gathered in Ewing’s cramped office and had to hide their papers whenever he had a visitor. And as they stared at the rows of meaningless letters and numbers that were arriving daily at the Admiralty, they had very little idea either of what the signals meant, or where to start in attempting to make sense of them. Meanwhile, however, developments were also taking place elsewhere.

  Less than a week after work had begun, General Sir George Macdonogh, the Director of Military Intelligence in the War Office, approached Ewing. The army, too, were starting to receive intercepts of German messages but could make nothing of them. He suggested that they pool resources and try jointly to decrypt some of the messages. Accordingly, in a passing spirit of collaboration, Denniston and a couple of others spent some time at the War Office, but the rivalries and suspicions between the army and the senior service were too deeply entrenched for anything much to come out of this period of cooperation.

  By contrast, the Germans made a good start in the intelligence war. In the first major battle of the conflict, at Tannenberg on the Eastern Front at the end of August 1914, they were able to listen in to all the Russian radio communications, including precise orders as to where specific units were to locate. Because the Russians had very few trained radio operators and lacked any encryption system, nearly all of this information was sent unencrypted or ‘in the clear’. All the Germans had to do was tune in to the signals and translate them from Russian, and the entire Russian battle plan was revealed. With this intelligence the Germans were able to marshal their forces correspondingly. They moved several divisions very efficiently by railway from one side of the vast battle zone to the other, and the result was a massive German victory. For relatively small German losses, the Russians lost 78,000 killed or wounded, and 92,000 men were taken prisoner. After a second victory in early September, the Russian Second Army was almost completely wiped out. It took the Russians six months to recover from the disaster. It was clear that this was going to be a war in which listening in to the other side’s radio communications would play an important part.

  Although the Royal Navy had begun the war by taking the dramatic and pre-emptive step of destroying the German undersea cables, they had no plan as to how to intercept the radio signals that the enemy would then be forced to send. Since 1908, when a leading scientist from the Marconi company, H.A. Madge, joined the Admiralty as an expert on long-range wireless telegraphy, most naval vessels had been equipped with on-board radios. This led to a revolution in the way the world’s navies operated. Instead of admirals being in charge of their fleets and captains their vessels once they were at sea, they were now subject to control from the Admiralty in London. Only at the Admiralty was a full strategic and tactical overview available. As Churchill, First Lord in 1914, wrote, ‘from its wireless masts or by cable it [the Admiralty] issued information often of a vital character to ships in many instances actually in contact with the enemy. It was the only place where the supreme view of the naval scene could be obtained. It was the intelligence centre where all information was received, where alone it could be digested, and whence it was transmitted wherever required.’4 The German navy had an equivalent in the Admiralstab in Berlin and used a powerful transmitting station at Nauen outside the capital to send long-wave radio signals around the world. It was these signals that naval intelligence was intercepting in abundance, though so far it had no way to interpret or understand them.

  Although the science of radio was still in its early days it had grown well beyond infancy. Better tuning of equipment, finer calibration of transmitters and receivers had all greatly improved radio signalling and reception, and a network of amateur radio enthusiasts had grown up. In the years before the war, there had been a public scare about German plans for an invasion of Britain, and popular novels had helped to fan the flames. Erskine Childers’ classic 1903 thriller The Riddle of the Sands had depicted two young men discovering a plan for a German invasion of Britain while on a sailing holiday in the Baltic. In 1909, another popular novelist, William Le Queux, wrote Spies of the Kaiser, in which the fiendish Germans used wireless telegraphy to send information back to Germany about the movement of Royal Navy vessels in the North Sea. The idea of secret agents sending intelligence reports to Germany from underg
round radio stations took hold in the public imagination. And so, on the declaration of war, the Defence of the Realm Act closed down all amateur radio stations. This closedown provided an unexpected boost for the navy.

  At the outbreak of war there was only a single Admiralty longwave listening station, sited at Stockton-on-Tees near the Durham coast. This station was not going to be up to the task of listening in to a wide range of enemy signals sent on many different frequencies. However, a saviour appeared on the scene. Russell Clarke was what used to be called a ‘radio ham’. A barrister and an amateur radio enthusiast who, with an eccentric friend, Colonel Hippisley, a Somerset landowner, had before the war tuned in to German naval signals for fun. He went to see Ewing and told him that the Germans were transmitting many more signals, and at shorter wavelengths, than the navy realised. Clarke said he would be prepared to intercept these signals if granted official facilities to do so. Ewing gained permission to set Clarke up with his own listening post, and Clarke chose the coastguard station at Hunstanton on the coast of the Wash near King’s Lynn in Norfolk. This was ideally suited to pick up German naval radio signals sent out across the North Sea. The expanded station was staffed by GPO engineers and under Clarke’s instruction soon began to intercept a growing number of signals. Ewing also approached the Marconi company, who agreed to set up three separate listening stations to intercept naval signals. Before long there were eleven stations around England receiving a range of messages, all of which were duly transcribed and dispatched to ‘Ewing, Admiralty’. The nation’s first ‘Y Service’ or wireless listening service had been created.