Reaping the Rewards of Co-Operation. Franco-British Intelligence Sharing during the Gas War, 1915-1918

Based on British and French archive material, this paper seeks to contribute to the limited “coalition warfare historiography” by exploring a neglected but revealing aspect of Franco-British chemical warfare between 1915-1918: Intelligence sharing. A contextual overview of the two allied intelligence services prior to and following the outbreak of war highlights their complementary strength and global reach. The tactical and strategic significance of French and British intelligence failures at the time of the first German poison gas attacks in April 1915 is examined and contrasted with subsequent allied experience. The discussion focuses upon the two most productive sources of allied intelligence information, mainly reports from secret agents and enemy prisoner of war interview digests. The volume, quality and detail of this material, and its importance to the Franco-British gas war effort are underlined. The article demonstrates how closely and effectively the two allies co-operated by exploiting their shared intelligence data to successfully anticipate German initiatives and to mitigate the searching battlefield challenge posed by an enemy whose technological superiority and resource advantages were evident especially during the earlier periods of the gas war on the Western Front.

unsuspecting and unprotected allied troops. Despite being almost entirely unprepared to conduct such a form of warfare, Britain and France hurriedly responded to the enemy challenge and retaliated in kind five months later at Loos and Champagne respectively, albeit from an inferior resource and technological position.
It is important to underline the scale and implication for the allies of this new and chilling initiative in modem industrialized warfare. During the gas war of 1915-1918 the French army alone deployed 11 tons of poison gas. For their parts the British and Commonwealth armies used 6,000 tons while the Germans expanded a far greater tonnage of gas against the allies than the combined Franco British totals. The chemical war added pressing new imperatives for closer cooperation between the two major western front allies, one area of which forms the subject of the present discussion: intelligence sharing.

Anglo-French Intelligence Sharing and Historians:
At the time of the outbreak of World War One all armies were aware that they could be, or were spied upon. In response they resorted to a number of ploys-such as dispersion of forces, camouflage and secrecy-to conceal information from the enemy. Intelligence became vital in the pursuit of tactical, operational and even strategic advantage. Yet, at the same time, it became more difficult to penetrate the barriers of secrecy and deception created by the enemy and thus piece together accurate intelligence evidence which would be available in time for commanders to exploit. After April 1915, following the shock of Second Ypres, the gas war added an additional and daunting headache for French and British military intelligence. Yet, surprisingly perhaps, there has been no focused examination in the literature of what became an important aspect of Franco-British co-operation in the great gas war.
As historians specializing in intelligence issues have emphasized the nature and scale of the First World War posed profound challenges to both the French and the British organizations. (Note 1) Institutional growth was a joint response to these challenges but in Britain there was a far greater degree of re-organization as well. (Note 2) Its Directorate of Military Intelligence eventually expanded into eleven sections and employed a staff which, by 1918, exceeded 6,000. (Note 3) It is also relevant to highlight the relative strengths and weaknesses of the two intelligence communities as France and Britain faced up to war with Germany in 1914.
In a recent monograph about British military intelligence in the First World War, Matthew Seligmann has discussed the implications of Britain's reorientation of her foreign policy in the early years of the twentieth century. Britain had previously regarded France and Russia as its most dangerous potential rivals while viewing Germany as a possible collaborator in containing a Franco-Russian threat. With Germany now identified by the British Foreign Office as the most destabilizing factor in the European balance of power, it was to France and Russia that Britain turned for support. (Note 4) Now that Germany was considered the new protagonist, much more detailed information was needed about its industrial and military capabilities and its strategic intentions. (Note 5) In particular, the British were anxious to know 3 Published by SCHOLINK INC. more about the tactical precepts behind German fighting methods, the levels of training given to German soldiers, the specifications and performance levels of German equipment and a host of related matters.
Unfortunately, very little survives in the British archives relating to the raw intelligence received by the War Office about pre-World War One Germany. Much of this information emanated from four major sources: reports of British officers travelling through Germany, reports produced by various (British) government departments, open source materials such as newspapers and finally, espionage. (Note 6) With the coming of war, with the exception of spying, these peace-time avenues of intelligence would largely disappear. But there was a fifth source: Britain's new entente partner. As Seligmann has argued: …The French were another significant source of information about which the (British army) staff lectures and printed memoranda were discreetly silent. This belied their importance. (Note 7) According to Seligmann the French were "extraordinarily successful" in obtaining confidential data about the German army thanks to the skill and professionalism of the French Second Bureau's clandestine intelligence coups. (Note 8) The problem for the British military intelligence community at the time was that they only received information that had been filtered by the French and based upon what they judged to be relevant. Even so, the British military authorities and their intelligence staff in particular received a significant amount of information from a diverse collection of French intelligence sources. (Note 9) Unfortunately, Seligmann did not extend his investigation into the area of shared intelligence and gas warfare.
An important recent addition to the specialist literature of British military intelligence in World War I is James Beach's doctoral thesis. (Note 10) Unlike earlier studies, this work examines the development of the intelligence system throughout the war with particular reference to the major source categories of intelligence information. Beach also assesses the organizational structures, leadership and composition of British military intelligence personnel to explain how the credibility and influence of their findings were shaped; while details are provided of the analytical techniques employed during the various stages of the intelligence gathering and interrogation process. (Note 11) Of particular relevance to the present discussion is Beach's investigation of the various British frontline sources of intelligence including captured German documents (and other materials) and information supplied by enemy prisoners. Douglas Porch, in his study of the French secret services has maintained that while the First World War "revolutionized" French military intelligence, the service nevertheless entered the war with a number of assets. Their spying organization in Germany had a proven record of success, the fruits of which had been shared with their British allies. The French had also anticipated the importance of aircraft in the intelligence war, not just as the eyes of the army but for broader reconnaissance functions. (Note 12) Porch also stresses French recognition of the key role of what he calls "electronic" warfare, in particular telephone tapping and cipher decrypting. (Note 13) However, when the French intelligence services were tested at the time of the first German poison gas attack, they were clearly unable to alert the military high command of the impending tragedy. Unfortunately, Porch can throw no light on this matter largely www.scholink.org/ojs/index.php/wjssr because he did not investigate the connection between the French intelligence services and their involvement in the gas war. And, apart from one minor reference, he did not discuss Franco-British co-operation in the gas war either.
Yet, if Beach, Seligmann, and Porch as specialist intelligence historians have not fully explored the role of French and British intelligence sharing during the gas war, nobody else has produced a closer study of the area. Indeed, many historians of the war on the Western Front do little more than gloss over French and British intelligence co-operation in general, let alone expand their analysis by connecting chemical warfare co-operation with the work of the allies' secret services.

Franco-British Intelligence Co-Operation on the Western Front
Allied intelligence gathering in the gas war occurred in two geographical levels. One involved the utilization of the French and the British global spying networks while the other saw the interchange of more local but detailed information between the two military intelligence services operating out or close to the western front. The specific major intelligence sources were reports from secret agents and information supplied by enemy prisoners of war. A fragment in Joffre's memoir about the First World War is suggestive of their importance: Up until now, what we had were only hints about the attack. The first alarrn was raised by prisoners on What allied records do survive immediately following this episode concern urgent reciprocal requests from both armies for specific technical details of the German chemical attacks. The role and significance of German prisoner of war information within the larger picture of allied intelligence sharing in the great gas war is worthy of special mention.

Prisoners of War and Allied Intelligence
Both the British and the French High Command appear to have identified prisoner interrogation as a vital avenue of intelligence information about the enemy's use of gas warfare. (Note 21) The evidence that remains provides a valuable insight into the range, detail and sensitivity of information that was communicated to the allied interrogators by German prisoners-as will be demonstrated by a selective, but representative examination.
What is immediately striking about this evidence is how willing so many German prisoners were, or  (Note 31) In the relatively quiet period of trench warfare, prisoners would usually be taken singly or in small groups. This presented no real challenge for the intelligence staffs and they were therefore expected to subject each one to a full examination. (Note 32) The complication came during amid active operations when considerable numbers of Germans were imprisoned by a mixture of British units and the demand for intelligence was at its highest. It was known that a prisoner's psychological condition on capture was in the main a "confused combination of stupor and surprise" and that the most valuable interrogations occurred as soon as possible after capture. By September 1915 the central point for this critical processing was the division. Around ten percent of the prisoners would be exposed to a "quite cursory" interrogation in order to secure instant recognition of the German units engaged and to meet any compelling tactical intelligence requirements imposed by the divisional staff. (Note 33) During the mobile operations of late 1918 the divisional intelligence staff would proceed ahead of the leading brigade to carry on this early questioning. Accordingly, most prisoners were hastily moved back to the Corps "cage" where they were subjected to full examination and in several instances, thorough interrogation. A small number of prisoners, mainly specialists, would be sent to Army headquarters and in some cases to General Headquarter for their examination. These prisoners of particular interest would be "kept at Army [headquarters] until everything [they knew] had been extracted from them. (Note 34) Beach argues that the procedure of questioning prisoners developed as the war continued. The most convenient location was a particular room within the "cage". (Note 35) This was arranged to undermine the sang-froid that prisoners often retrieved by the time they arrived at the Corps "cage". The British intelligence officers generated the ambience of an "orderly room" whereby the prisoner would be marched in, stood to attention and subjected to exhaustive questioning in an authoritative fashion.
Besides their linguistic and psychological abilities, British interrogators could request other services to support them in their work. (Note 36) By 1918 the British were likewise engaging native-speaking decoy prisoners, known as "pigeons" as well as installing listening apparatus in order to acquire "unwitting" information from prisoners. (Note 37) The general contribution to intelligence made by prisoners cannot be underrated. In 1917, the Second Army maintained that it was the most conspicuous of all their sources.
Furthermore, some prisoners also provided unequivocal insight into matters of strategic gravity. The most valuable were deserters. (Note 38) Although no detailed investigation into the methods the French intelligence services employed to extract information from their POW's has been published, what the present discussion-concerning the gas war-would indicate is that both allies were highly successful in obtaining detailed and valuable intelligence from German prisoners of war. Moreover, the volume of POW gas war intelligence information increased during the summer and autumn of 1918 even though, as Beach points out, German soldiers were better informed about what to expect from their British inquisitors as the war progressed.
(Note 39) But why did the enemy prisoners reveal so much to the allies?
There is a complicating factor which could throw light on the POW issue. This concerns the absence of explicit, precise and unequivocal wording in the international conventions that then applied to the rights and obligations of prisoners of war. During the First World War deficiencies in the Hague Conventions of 1899 and 1907 concerning the treatment and rights of prisoners of war were highlighted. In particular, the implications arising from the imprecise wording within a number of its Articles had become a source of concern. Some of these defects were partly remedied by special arrangements made between the belligerents in Berne in 1917 and 1918, but it was not until 1929 that what is popularly known as the Geneva Convention was adopted by many nations. Significantly, Part II, Article 5 of the Convention states: No pressure shall be exercised on prisoners to obtain information regarding the situation in their armed forces or their country. Prisoners who refuse to reply may not be threatened, insulted or exposed to unpleasantness or disadvantages of any kind whatsoever.

Espionage and Franco-British Intelligence
The other major channel of information in the gas war was spying. Unfortunately, given the clandestine nature of espionage, especially in wartime, the primary source materials relating to raw intelligence in the French and British archives are correspondingly thin, being far more incomplete than those relating to prisoner of war intelligence. All that can be attempted here is a qualified but selective overview of the contribution of spying to the allied gas campaign with special reference to the mutual exchange of intelligence information. It is perhaps necessary to begin by underlining the implications of the very affiliates and of the work of German-owned electro-chemical plants there. On a related theme, German control of nitrate production in Chile was the focus of Chevalley's report of 31 May. He pointed out that having invested 125,000,000 marks the Germans had come to monopolise the output of Chilean nitrate factories which were producing 500,000 tons of the chemical annually. (Note 50) Later, in a letter dated December 7 1915, Chevalley disclosed how the German army was producing large quantities of a new gas based on bromide and chlorine to be used, in part, as a shell filling and possibly as an aerial weapon.
(Note 51) An examination of the German army's subsequent gas attacks in late December indicates that the enemy did indeed employ this new chemical agent but not, as it turned out, from aircraft.

Conclusion
In this examination attention has been drawn to the importance, openness and extent of intelligence sharing in the gas war and of the exploitation of allies' global intelligence networks. The value to both countries of sharing their extensive prisoner of war intelligence "confessions" has been stressed with reference to both French and British archival material. Elizabeth Greenhalgh in her Victory through Coalition has lamented that it was a "tragedy that vitally necessary co-operation was achieved more easily in the civilian (bureaucratic) sphere than in the military sphere". (Note 52) While the findings of the present, more narrowly focused, investigation endorse this judgment on a general level, the specific areas of gas war co-operation point to a more complex picture of allied achievement. (Note 53) Of the major areas of Franco-British co-operation in the great gas war, the importance and success of intelligence sharing is probably the most difficult to assess in view of the more fragmentary state of the archive evidence. However, its significance can perhaps be appreciated negatively. The allies were from the beginning and throughout much of the gas war in a disadvantaged position, as far as research, production and offensive tactics were concerned. Following the major intelligence (and operational) failure at Ypres; it became all the more important for the French and British to forestall German chemical weapon initiatives by effective and wide ranging intelligence activity. By closely sharing their intelligence finds the allies, arguably, further reduced their chances of being caught unaware by their powerful enemy. In the event, there were relatively few major surprises in store for the allies which they had not found out about the advance. Even the German introduction of mustard gas in 1917 was, in part, anticipated by allied intelligence.