The secret war 1914-1918 part one--the land war.

Espionage in war is as old as history. The Israelites under Joshua inserted spies into Jericho to reconnoitre before their attack. The Assyrians created an entire section of government devoted to intelligence. In all his campaigns, Alexander of Macedon used both strategic and tactical intelligence to conquer much of the Middle East, and part of Central Asia. But even before Alexander, the Chinese ruler Sun Tzu advocated in what was probably the first published treatise on war, the use of spies to obtain "foreknowledge" of potential enemies. Later, Wellington took great pains and spent much gold to 'look over the hill' at his Napoleonic adversaries, who had a complete ministry devoted to intelligence. However, in the twentieth century technological revolution changed utterly the nature of intelligence gathering. Electronic warfare began almost immediately war was declared in 1914; and for the succeeding four years the Central Powers and the Allies waged a secret war against the other. Beginning with a few radio sets and a handful of operators, by 1917 each side had created vast organisations, to electronically attack and counterattack the other by physical and electronic means. After the end of World War One, every major nation continued to secretly develop some aspect of electronic warfare, which was destined to play a major role in World War Two. But not until the last quarter of the 20th Century did knowledge of electronic warfare become widespread. It had been the Ultra secret of all nations. This article will concentrate on the development of British electronic warfare during World War One.

Electronic Warfare on the Western Front

Despite the experience of the South African War and successive reports following annual manoeuvres; the British Army was unable to form a separate Signal Service for their field army. Disagreement regarding "the minimum of intercommunication services considered necessary by the General Staff, and the maximum expenditure which could be admitted by the Finance Member of the Army Council," delayed its formation until 1911. (1) When agreement was finally reached, it was because a British Expeditionary Force for service on the continent of Europe had become British government policy. A Signal Service was formed in 1912, but because of financial considerations the Army Signal Service (ASS) remained part of the Royal Engineers; and its modest scale of equipment and manpower establishment, 75 officers and 2,346 NCOs and men, reflected the belief, and desire, that any future war would be short.

Radio Telegraphy 

The security implications of using wireless telegraphy in field operations was well know, and the mistrust in which codes and ciphers were held by staff and Signals ensured that wireless was hardly used by the BEF during the early years of the war. Initially, staff officers preferred line telegraphy for intercommunication, because it produced a written record; however, the telephone rapidly gained favour and its use became widespread. Like all units of the BEF, although superbly trained, the ASS was severely stretched during the encounter battles of 1914. In the fluid operations of August--November, although high precedence messages and verbal orders were transmitted by telegraph or telephone, the despatch rider letter service (DRLS), delivered by cyclist, motorcyclist, or mounted orderly became the principal method of passing messages. There was, therefore, no security problem; although on several occasions messengers failed to get through, messages not delivered, and units cut off. Radio was not used during the encounter battles of the BEF, except to maintain contact with cavalry formations acting independently. (2)

Because the available radio receivers were not used in a communications role, the radio operators manning these sets turned their attention toward intercepting enemy radio communications with good results. Additionally, during October 1914, the BEF Signal Service received a 'wireless compass'. This, a Bellini Tosi directional receiver, modified by Marconi incorporating the vacuum diode valve invented by Professor Sir John Fleming of University College, London. Fleming also coined the word 'electronic'. That instrument was highly successful in locating enemy headquarters; and the results galvanized radio interception in the BEF. With the new valve, receivers were improved and as they became available, a line of these stations was deployed behind the front out of enemy artillery range, and gained for the BEF Intelligence "a weapon of incalculable value ... [and] contributed in no small degree to the efficiency of the British Intelligence Service." (3) The British were helped in their secret war by the attitude of the German General Staff to the use of radio communications in operations. Field-Marshal Hindenburg attributed his success at Tannenberg to intercepts from Russian communications. Consequently, as late as the spring of 1917 he remained resolutely against the use of radio in the field; he was however, overruled by the General Staff in Berlin. (4) For their part, the British seldom used radio on the Western Front until 1917, and radio did not become the first line of communications until mobility returned to the battlefield in 1918, and then only when stringent security precautions were followed.

Line Telegraphy and Telephony

When the battle lines were formed from the North Sea to the Swiss frontier in November 1914, the combatants settled down to the problems of static positional warfare. The battlefield became a mass of zigzagging saps and parallel lines of trenches, fronted by vast aprons of barbed-wire, dominated by almost ceaseless machine-gun and artillery fire. Upon this vast body of mutual destruction the signal services of the combatants laid their opposing communication cable systems; each in their various ways as extensive and intricate as the nervous system of the haman body. The British eventually opted for rigid sector grids of buried cable, a system, which encompassed operational flexibility by the ability to bypass shell-damaged sections. (5)

During 1915 British military intelligence became aware of many manifestations of an informed enemy on their sector of the Western Front. Even the most carefully planned and executed minor trench operations were met by well directed artillery, machine-gun and small arms fire; new British artillery or machine-gun positions were subjected to bombardments even before they had opened fire. Sudden bombardments would take place at the precise time relief was being effected on a unit sector, when trenches were filled with double their normal complement; or on quiet sectors the incoming unit would be greeted with welcoming notices being hoisted over the German lines, even with the name of the relieving regiment. British liaison officers with flunking French formations reported similar occurrences on their sectors. Such obvious evidence of enemy prior knowledge and preparedness, gave rise to spy mania in rear of the battle areas; sometimes with comic overtones or tragic outcomes. Yet despite all precautions in countering espionage, leakage of information continued with grievous effects for frontline troops.

At much the same time, in mid-1915, users of the British military telephone system, a gigantic cat's-cradle of wire throughout the forward and rear areas, were experiencing considerable trouble from cross-talk. It had reached such proportions that when an officer picked up a phone in either a trench dug-out or headquarters office; "he was never sure who would answer". (6) The possible correlation between cross-talk and leakage of information demanded and was given the closest attention by both the Signal Service and Staff Transmission of electromagnetic energy through space had been proved by Sir William Preece in 1892; however the conductivity of earth was scientifically unproven. Once again UK scientists were asked to help and proved earth could conductor voice or telegraph electromagnetic radiation. Knowing how involved German scientists--such as Ohm, Gauss, kenz, and Hertz--had been to the development of both electricity and wireless, Signals officers were already alert to the possibility of eavesdropping electronically, when a report was received from the French Signal Service of German attempts to tap into French artillery wires; by running connecting wires along a stream bed into the French positions. (7) Given that there were railways, pipelines and watercourses bisecting the frontline this was comparatively easy. Experiments began to test the theory of earth conductivity in forward areas.

Initial British experiments took place in First Army area using a wireless receiver with additional reception coils. Even with this Heath Robinson arrangement, telephony reception was obtained at 100 yards and telegraphy at twice that distance. (8) The possibilities of using the technique with improved equipment to eavesdrop on the enemy were obvious. At the same time, experts in the Signal Service realized the importance of instituting measures at source to deny the enemy eavesdropping facilities, and also to institute Staff measure to make all telephone users aware of its security limitations. However, human nature and a mistaken sense of security when speaking on the telephone, together with inexperience, combined to thwart all efforts to prevent misuse of the telephone in forward areas. For a considerable time, well into 1917, leakage of information continued.

The earliest authenticated information that the Germans had a listening apparatus came from a British civilian who had been interned for a time in Germany. In the hospital at Ruherleben Camp he had overheard a medical orderly tell visitors at the hospital of an apparatus at the front through which valuable information was being obtained. As early as September 1915 German prisoners disclosed that stringent precautions had been taken in the German lines on the use of the telephone long before these were initiated on the British front. Conclusive proof of the efficacy of the theory of earth conductivity and the source of German tactical intelligence was given when a French infantry conscript, who had been a civilian electrician, constructed a primitive listening-set. It was an apparatus consisting of no more than the ganging together of two civilian telephone receivers. These were connected in parallel to a length of cable laid through tunnels and saps to a position close to the German front line; the cable-cores were then connected to a spread of empty 75 mm shell-cases buried in charcoal. In a dugout within the French front line, the French soldier tuned his 'set' for maximum sound and an interpreter overheard faint German conversations. (9)

The news of the seminal listening post experiment and its results was passed by liaison officers to the British. From then on, French and British Signal Services cooperated closely. Firstly, to immediately instigate countermeasures to deny leakage of information; and secondly, exploiting this new discovery.

Allied Countermeasures

Casualties during the first and second battles of Loos between September 1915 and April 1916 reached serious proportions; at the same time vast preparations were already in-hand for the 'Big Push' due to commence in June 1916. Both events concentrated wonderfully the minds of Signals and Staff of the BEF on security and intelligence. To protect one, and exploit new technology for the other became a technical priority to both protect and exploit. One of the first Army measures was to create the Intelligence Corps in 1915, and staffed it with many German linguists.

On the technical side, Signals experts devised a new type of perfectly insulated twisted pair cable known as 'metallic'; which was to be used in what was considered to be the 'danger zone'--1,000 yards from the front line trench. Orders were placed immediately in England for the cable, but it did not arrive in large quantities until the end of 1916. Meanwhile a major cleanup of disused field cable and multi-core cable was undertaken throughout the frontline. This was a task of major proportions for the personnel available. In the Somme sector alone there was 43,000 miles of overhead cable behind the lines and in the front itself there was a further 7,000 miles of cable buried to a depth of six feet, in addition to "large quantities" of ground laid cable. In Ypres, which was almost continually under shellfire from heavy siege artillery, the medieval sewers were used. In places small boys were paid to carry string through narrow sections to pull cable through. (11) Until the task was done there was no rest, "even for the gumbling so dear to the soldier's heart". (12)

Early Precautions on Forward Telephone Circuits (13)

In addition, orders were distributed to all telephone users outlining forbidden subjects of telephone conversation; unit names and code words, movements, artillery locations and shellfire results. Precautions which later were taken for granted had to be enforced by disciplinary action in 1916-17.

Despite all warnings, breaches of telephone security continued. Casualties throughout the Somme battle were horrendous. Fortress villages were captured after prolonged siege and many repulses. When the village of Ovillers-la-Boisselle was finally captured in this way, a complete copy of a BEF Corps operation order was found. Investigation revealed it had been passed over forward telephones by a Brigade Major to one of the battalions, despite his protestations, on the express order of his Brigadier.

   Officers could not be made to understand that half their own
   worries and a considerable proportion of the casualties suffered
   by their units were due to their own indiscreet use of forward
   telephones ... It was not until disciplinary action was taken and
   carelessness made the subject of a court-martial charge, that
   forward telephones were used with any degree of care. (14)

Since it was the Germans who initiated listening posts on the Western Front, it followed that they took great precautions to guard against similar attack by the British and French. Moreover, having a large prewar conscript standing army, with a commensurately sized dedicated and highly trained staff corps, their communication systems was better organized, trained and disciplined to resist electronic attack than the British. This made the task of Allied eavesdroppers more difficult than those of the enemy. Using primitive listening apparatus it soon became apparent to the British staff that German security discipline in the forward areas was infinitely better than their own. With remarkable frankness the Signals historian recorded this was because:

   The possession of a more highly-trained Staff, the stricter signal
   discipline of a conscript army, the better material available for
   the making of linesmen and operators in a nation long trained in
   bulk for war, and, lastly, the more workmanlike system of trenches
   in which his lines were laid. It is not surprising therefore, that
   at first attempts, little German conversation was overheard. His
   circuits were fewer and better controlled. His signal discipline
   was good both in the Signal Service and rank and file of other
   arms. (15)

However this situation was to change when better listening sets became available. In February 1916 the French Signal Service produced a listening-set incorporating the triode valve they were already using in a wireless-compass. Utilizing three triode valves in a sound-frequency amplification circuit, they produced what the British called the I.T. Set; it was an instant success. Revolutionizing as it did the possibilities of covert listening, the Allies immediately increased the depth of their own 'danger zone' from 1,000 yards to 3,000 yards. This meant that telephone conversations forward of brigade headquarters were at first restricted to urgent messages then completely forbidden. Because it was realized, that in the circumstances of the 'zone of frequent shelling', cable insulation could not survive completely intact for very long; damaged insulation meant leakage to earth and that risked detectable radiation. It was yet another measure of the seriousness of the threat to information security. Signals and Intelligence officers warned the general staff that telephone discipline rather than technical advances was the only sure way to safeguard security.

To prove this point, some I.T. sets were used in a self-monitoring role as well as eavesdropping. In the middle of the battle of the Somme, September 1916, a single station policing just 3,000 yards of the British sector in a period of one month, heard over thirty units mentioned by name, including one army and several divisions; troop movements were mentioned, forthcoming operations discussed: whole operation orders quoted; even the report of fifty casualties by 'friendly fire'. Grimly the official historian commented:

   It would not have been surprising if the German Intelligence
   Service had been able to reconstruct from its listening set
   reports practically the whole constitution of the British Army
   as it existed at that time, and to anticipate the most
   jealously-guarded intentions of the Staff. (16)

Breach of security reports submitted to the Staff eventually did have their effect. But limited resources meant that only a few divisions could be monitored at one time, therefore improvement was slow. It was, moreover, achieved only by severe disciplinary action; but the corollary of disciplinary action against transgressors to telephone security was the ostracism of listening-post personnel. In forward areas, host infantry units had to be detailed by explicit orders even to obtain rations and accommodation for them. "In the early days it [life] was made as uncomfortable as possible both by the enemy and by our own forward troops." (17) However stem measures did eventually proved effective; by the end of the Somme battle in November 1916 leakage of information by telephone had decreased considerably. Yet the BEF Signals Service by necessity had to continue monitoring its telephone users until mobility returned to the Western

Front in 1918.

The Allied Listening Post

The first two I.T. sets used by the British in an eavesdropping role were deployed near Vermelles in January 1916 opposite the Hohenzollern Redoubt. The longer range of the new set, probing as it did beyond the rigidly disciplined frontline and support trenches into the comparatively relaxed rear areas, greatly improved the flow of intercepted German conversations. And with it came a constant flow of exploitable intelligence. As the flow of listening sets from the manufacturers increased so did the flow of intelligence and the demand for suitable personnel to man the listening posts. The BEF and home army was trawled for German speakers, and a new army trade interpreter-operator was created. Trained in both set handling and Morse code, they were destined to lead a hazardous existence operating either in the frontline trenches or saps deep in no-mans-land.

The I.T set, augmenting and corroborating as it did the radio intercepts, Allied intelligence gathering on the Western Front was revolutionized. As the flow of raw intelligence increased so did the necessity for a sophisticated organization for collation, analysis and confirmation of raw material, and the dissemination of the finished product to users by secure means. By 1917 Intelligence Centres of mixed Intelligence Corps and Signals personnel were established at each Army headquarters. Although evolved independently, all Centres had dedicated communication circuits for intelligence traffic to and from Corps, Divisions, RFC headquarters, listening- posts and direction-finding stations; and lateral links to flanking Armies, and rearwards to GHQ BEF. In the secret war, interception, code breaking and direction finding was widely used; however, radio jamming was used sparingly by both sides because it interfered with own transmissions. Photographic interpretation was added to intelligence specialization when aerial cameras were introduced to air force observation squadrons; and aerial reconnaissance was often used to corroborate intelligence gained by other means. Unfortunately, this only covered the front line. The massive German build-up behind the lines of March 1918 went undetected. By the end of 1918, with the exception of deception and radio jamming, most aspects of 20th century electronic warfare was developed at these centres.

The German Final Throw

While doubt and disagreement attended the French and British staffs as to its start date and probable thrust lines; none doubted that a great German spring offensive was planned for the spring of 1918. Naturally the German commanders played on the doubts and fears of their opposite numbers with widespread deception. Their intention was to deceive the French; crush the British by two massive blows, on the Somme and then the Lys, aimed at driving a wedge between the Allies and capturing the channel ports. With this achieved, they intended to overwhelm the French on the weak Chemin des Dames and steamroller through to Pads. The eventual battle came close to success; but although the Allied lines bent they never broke and ultimately for the Germans it proved a pyrrhic victory. They lost the ability to holdout for a stalemate settlement in 1919.

Corroborated Intelligence and the German 1918 Offensive

In war it is inevitable that intelligence from one source may be insufficient to convince a commander to a specific course of action. An important, if not essential aspect of intelligence is to obtain corroborative information from alternate sources, communication intelligence (Comint), electronic intelligence (Elint) or human intelligence (Humint). In the months preceding the great attack of 21 March 1918, despite much front-line information by comint and in May 1918 aerial photographic reconnaissance, there are two examples of humint which assisted Allied countermeasures in March and May 1918. The first was an almost insignificant news item in a newspaper obtained through Switzerland, which disclosed the interpolation of von Hutiers 18th Army opposite Gough's Fifth Army in March 1918 just before the attack on 21 March. Another example was about the Marne break-through on 27 May 1918; this concerned a German POW in British hands. Among his possessions was a postcard from a friend on the Laon sector; the message on it, in veiled language, indicated that his unit was about to launch an attack on the Chemin des Dames. That information, flashed to French GQG, gave General Petain two days warning of the massive third phase of the German Spring offensive; because it confirmed photographic intelligence. (18)

Security and the Black Day of the German Army

The Allied 95 day advance to victory began at Amiens on 8 August 1918. In many aspects it resembled the Cambrai attack of the previous year, chiefly the use of tanks, no preparatory bombardment, and security. In the relatively short preparatory period, great emphasis was placed on the latter aspect. The vast movement of troops, cavalry, armour, artillery and logistics was made only during the short summer nights. Moreover, every soldier in Fourth Army, which would deliver the initial blow, had been warned repeatedly about the need to maintain security. At this time, such was the secrecy surrounding the impending attack that no one outside Fourth Army was officially aware of it with the exception of Haig and his army commanders. Sir John Monash, the Australian Corps commander later wrote:

   The loss to us of a single talkative prisoner would have been
   sufficient to disclose to the enemy at least the suspicion, if
   not the certainty, that an attack was in preparation. (19)

On the night of 6 August a German raid on the 13th Brigade sector netted five Australian prisoners. Nor was that all; whether irritated by "incessant 'nibbling' activities of Australian troops" (20), or as part of a wider intelligence gathering raid, a heavy Germany raid in regimental strength supported by artillery surprised a unit of the newly arrived 58th British Division and captured 200 prisoners. Fourth Army held its collective breath; but no prisoner talked except to give his number rank and name. (21)

The move of two Canadian divisions to Fourth Army was cloaked by a deception plan, which moved two Canadian battalions temporarily to Flanders. It also involved a theatrical telephone conversation between two Canadian officers for the benefit of German eavesdroppers. The Canadians complained of the short notice move of their divisions to the Flanders front. At the same time planted rumours of a pending Canadian assault on Kemmel Hill. So successful was the deception, that it reached as high as King Albert of the Belgians; he complained to Marshal Foch about not being informed of a pending major attack within in his kingdom. (22) All Australia know the success of the attack on 8 August 1918.

The Middle East Secret War

During early operations in the Middle East against Turkey, during 1915 a radio intercept station was established close to the Great Pyramid near Cairo. Later, deception was used by General Sir Edmund Allenby before the Third Battle of Gaza to induce the Turkish command to believe his main attack was against Gaza; while in fact Allenby positioned his mass of manoeuvre against Beersheba. This was done through radio transmitted cipher messages 'intended to be deciphered' and other devices including the 'haversack ruse'. (23) This latter involved a staff officer on reconnaissance pretending to be chased and wounded, dropping a blood-stained haversack with a marked map and other documents. That evening a general routine order (GRO) was circulated ordering every effort to be made to find and recover the haversack. This was followed by a simply coded message, aimed at being decoded, to units in the affected sector repeating the GRO. German controlled Turkish intelligence at first suspected the veracity of the documents. But the efforts made to recover the haversack convinced them of its authenticity. The attack at Gaza sucked in the available Turkish reserves, and the attack at Beersheba broke the Turkish lines. (24)

A year later, before the final offensive in September 1918, by secrecy and deception Allenby massed on his left 35,000 infantry and 9,000 cavalry and 400 guns across fifteen miles, against 8,000 infantry and 120 guns; while on the remaining fifty miles front he had 22,000 infantry and 120 guns against approximately 23,000 Turkish infantry with 270 guns. When General Sir Henry Chauvel's Desert Mounted Corps moved from the Jordan Valley to the Plain of Sharon, his wireless detachments remained at Jericho passing dummy traffic; while mule teams in camps left standing, dragged huge bundles of brushwood to raise vast dust-clouds at horse watering times. Meanwhile, an hotel in Jerusalem was earmarked as the new GHQ, with telephone lines laid and doors marked for staff branch's. Of course the move never occurred. East of the Jordan Lawrence's agents were spreading rumours that much fodder would shortly be required at Amman. (25) When it came, by deception, surprise and audacity, Allenby's thunderbolt offensive achieved, without an effusion of blood, the complete destruction of the Fourth, Seventh and Eight Turkish Armies. Turkey sued for peace just six weeks after the commencement of the offensive; and the problem of the Middle East for the Western World began.

Conclusion

With the Battle of Amiens as its springboard, the Allied armies on the Western Front began a series of short sharp limited offensives, each following rapidly on the next; which in modern military parlance penetrated the enemy's decision-making cycle, shattered his cohesion and destroyed his will to fight. The return of mobility to the battlefield by the use of tanks and armoured cars, supported by ground attack aircraft, saw radio communications for command and control on the battlefield come into its own. But the Armistice of 11 November 1918 came too quickly for further development of electronic warfare. Nevertheless, despite major reductions in defence spending in the 1920-30's, passive electronic warfare continued. In the British Army this was restricted to detachments in China, the North-West Frontier of India and Palestine. There the 'great game' continued, providing electronic assistance to real life equivalents of Kipling's Creighton Sahib; replacing agents like Mahbub Ali and Kimball O'Hara. This time Soviet Russia was the adversary; although now under the red banner, Mother Russia had not abandoned her imperial expansionist policy.

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(1) Major R.E. Priestley. The Signal Service in the European War of 1914 to 1918. Institution of the Royal Engineers and the Signals Association. Chatham 1921: p5.

(2) Ibid pp. 28-29.

(3) Ibid p. 54.

(4) Ibid p. 151.

(5) Ibid p. 120. Curiously, in describing the gradual development of cable laying, from the haphazard development in the Ypres salient into a planned cable grid system, in and around Ypres and in other sectors as the British share of front expanded; the Official Signals historian compared Sydney's 'old world' street development, with the planned grid of Melbourne's streets.

(6) Ibid p. 100.

(7) Ibid pp. 100-101.

(8) Ibid.

(9) Ibid 102.

(10) Ibid plate XI.

(11) Ibid p. 119 fn.

(12) Ibid p. 12

(13) Ibid plate XII.

(14) Ibid p. 102

(15) Ibid pp. 109-110.

(16) Ibid p. 109.

(17) Ibid p. 108.

(18) Tuohy pp. 236-237.

(19) Sir John Monash. Australian Victories in France, Angus and Robertson, Sydney, 1936, p. 56.

(20) Ibid p. 77.

(21) Ibid p. 97.

(22) Ibid p. 80 fn,

(23) Wavell, Sir Archibald. Allenby, Harrap, London, 1940; p. 202.

(24) Major-General Sir G.G. Aston. Secret Service, Faber and Faber, London, 1933, pp. 194-195 and Tuohy pp. 283-284.

(25) Wavell p. 269