In October 1916, German “merchant” Eugen Steiner (1872-?) booked into the rather posh Hotel Krasnapolksy in the centre of Amsterdam. He had not come to the neutral capital to trade, but was sent by the German secret service as an agent. His assignment was to establish a network of informants and collect information on the Dutch military. He proved effective and even became “one of the dangerous spies active in the Netherlands”. The Dutch police, well informed about German activities in the capital, shadowed him but were unable to find enough hard evidence to take action. Police detective Karel Henri Broekhoff (1886-1946), who specialized in infiltration in the German community, mentioned Steiner’s reprehensible behaviour to the German vice consul, whom Broekhoff met regularly. Broekhoff explained he knew Steiner had brought the consul sensitive information on Dutch defence and that if nothing was done, the Dutch police would be compelled to interview the consul. This had the desired effect: the consul arranged for Steiner to leave Amsterdam quietly. Broekhoff in fact had bluffed: he had no evidence that Steiner had actually handed over such sensitive information to the German authorities.[1]

This small anecdote exemplifies the way Dutch counterespionage worked during the First World War: close contact between the police authorities, foreign agents and foreign representatives, and a “live-and-let-live” system so long as Dutch neutrality and internal peace were unaffected. The Dutch authorities had to be pragmatic, they knew that because of its geographical position Holland was of great importance to the warring states; they also knew huge numbers of foreign agents swarmed their territory while their own secret service was very modest indeed and lacked experience. This called for a pragmatic and practical approach, from which the Dutch could gain information while simultaneously remaining on friendly terms with their powerful neighbours.

Dutch Counterespionage and Intelligence Gathering: GS III

The Dutch General Staff established a counterespionage and intelligence service only months before the war broke out. The bureau initially consisted of only one officer, but it expanded quickly to almost thirty officers and conscripted academics. The main effort of GS III[2] was analysing foreign open sources. This gave the Dutch valuable insights in the developments within the belligerent armies. But many more new sources were tapped during the war years. Just to give some examples: foreign radio transmissions were monitored; thanks to the exceptionally gifted cryptologist Henri Koot (1883-1959) the Dutch managed to monitor and decode messages from foreign legations, and messages to and from German U-Boats. Moreover, German radio stations, in touch with U-Boats, were placed close to the Dutch border, which made interception relatively easy. In 1915, the Belgian army, with French support, erected a rather extensive broadcasting and listening station in the small Belgian enclave of Baarle-Hertog, which is surrounded by Dutch territory. The Dutch authorities were well aware of this impressive construction, which could be the target of German demolition attempts and thus endanger neutrality. The Allies thought the opposite was true: the Germans would never risk violating Dutch neutrality, with possible grave consequences, only to demolish a radio tower. The tower remained functional throughout the war and probably the Dutch were monitoring all activities closely.

Also, based on the legislation that gave the military extra powers in wartime, telegraph and telephone messages were monitored. Censorship gave the military the power to open mail and telegrams, but only when a reason for suspicion already existed and only in areas under military control. Nevertheless, postal censors were used systematically to forward information on belligerent countries and armies that they read in the mail to Army Headquarters in The Hague.

Furthermore, GS III questioned Dutchmen who had been traveling abroad for private, commercial or military reasons. Many leading Dutch entrepreneurs had important and extensive networks in neighbouring countries and the same applied to the military. For many decades the Dutch military had maintained close links with German arms producers and in times of crisis those ties were not suddenly severed.

It also worked the other way around. During the First World War, previously unimaginable numbers of foreigners crossed the Dutch borders: refugees, wounded soldiers, deserters, aeroplane and submarine crews who were interned, or Belgians fleeing their country to join an Allied army. Many of them carried information that could be important to Dutch security, so the police questioned them or, when technical military knowledge was concerned, the military did. The Dutch authorities also permitted German and English officers to question their interned comrades. A small number of the refugees were political opponents of the German Imperial government who had fled to Holland.

The border police collected important information as well. Some officers of the army and the military police were actively gathering information on any relevant military activity close to the border. Like some police commissionaires they built up their own small information networks. This in fact might have been the most active spying done by the Dutch during the mobilisation. Their information was sent to GS III in The Hague.

Furthermore, The Hague was full of representatives of belligerent states. We can assume contact with representatives of those states took place on an almost daily basis. At their legations, but also in clubs and at all kinds of social occasions Dutch officials met high-placed foreign officials, some of whom were known for their sympathies for the Dutch. These contacts were important occasions where the Dutch military could give a certain degree of insight into Dutch military preparations, thereby stressing the seriousness of these preparations against possible invaders.

To manage information from foreign attachés based in The Hague, GS III used three handpicked Dutch officers as liaisons to the representatives of the German, British and French army in The Hague. They were chosen for their well-known pre-war sympathies for, and their long-standing contacts with, those armies. None of their reports has survived, but circumstantial evidence suggests they were important because the belligerents trusted them and used them to exchange information, thus circumventing any direct contact between the Dutch intelligence authorities and belligerent military representatives.

Two other sources of information were of great importance and very actively used by GS III: newspaper correspondents and the Dutch military attachés. Dutch neutrality offered the opportunity to collect news from all sides, and travel to all countries relatively freely. It also more or less required the Dutch press to report on international developments even-handedly, and that added to the authority of Dutch reporters. The governments of the warring states actively maintained contacts with Dutch newspapers in order to influence their reports and to influence Dutch public opinion. Both the British and the Germans established extensive networks to achieve those aims as part of their general propaganda effort. One can conclude that the British propaganda service was closely related to a number of Dutch newspapers and to a number of prominent Dutchmen well known for their Allied sympathies. Dutch journalists, some of whom had close personal contacts with colleagues and politicians in the belligerent countries could travel to belligerent states relatively easily, therefore were used to gather information. The Germans in their turn often gave their spies the public appearance of a newspaper correspondent and they financed De Toekomst (The Future) a Dutch weekly that promoted German war aims. Dutch GS III in fact used journalists the same way: when returning from abroad they would be debriefed in The Hague.

After years of pressure by, amongst others, GS III, the Dutch government in 1916 finally agreed to send military attachés to Berlin, Paris, London and Bern. These officers quickly became important sources for detailed military information, not only based on their networks in the capital cities, but also on many travels to the front line and to military installations and factories. Extensive reports on weapon technology and military organisations, as well as the morale of soldiers and civilians, were sent to The Hague. Occasionally they even talked to the belligerent commanders-in-chief or heads of state. It is interesting to note that the government and parliament stressed explicitly that the attachés were to refrain from spying. Perhaps the government feared foreign accusations against its attachés or it thought of spying by its representatives as an illegal activity that could compromise Dutch neutrality. The officers nevertheless proved their worth.[3]

British Espionage in the Netherlands

In 1914 naval officer George Cumming (1859-1923) of the SIS, led the British service for espionage abroad. He had set his sights on the Netherlands since the outbreak of the war. His main agent in Holland was Richard Tinsley (1875-1942), a former merchant marine officer who had lived in Rotterdam since 1909 as managing director of the Uranium Steamboat Company. As soon as the war broke out, Tinsley struck up a close relationship with the British consul-general in Rotterdam, Ernest Maxse (1863-1943), and the British military attaché in The Hague, Laurence Oppenheim (1871-1923). In his hometown, Rotterdam, Tinsley was constantly in close contact with the Rotterdam police, to their mutual benefit.

Tinsley’s organisation grew exceedingly rapidly in size and effectiveness. It became the largest and most important network controlled by Cumming in London. Since 21 percent of all British agents abroad were posted in Holland, half of Cumming’s budget, 5000 British pounds per month, was going to Rotterdam. Tinsley’s network covered Holland, Belgium and Germany. He sent military information to London as well as information on Dutch smugglers who illegally transported goods to Germany. Tinsley also contacted left-wing German exiles in Holland and financed their publications.

From 1916 onwards the most important British agent in Tinsley’s organisation was Henry Landau (1892-1968) who built up one of the most successful information networks of the First World War. From Rotterdam he led a large number of passeurs (crossers of the Dutch-Belgian border which was heavily guarded by electric wire) and the hundreds of Belgian train watchers of the Dame Blanche organisation. This gave London a good insight into German troop movements to the front. Landau also interrogated German deserters, who fled to the Netherlands in great numbers, and observed German activities in Belgium from the Dutch border. He too exchanged information with the Dutch authorities regularly.[4]

Next to SIS, the War Office, the General Headquarters of the British Expeditionary Force and the Royal Navy used Dutch territory to get information to and from Britain, either by ferry or by telegraph. They were interested in, among others, the German military and in Belgian men, trying to make their way to Britain or France and of course in information produced by the Belgian resistance. Already in 1914-1915 for instance GHQ had sent its agents to Maastricht and Liège. In 1917 the Chief of the Imperial Staff, William Robertson (1860-1933), did not exaggerate when he stated, “the whole of our secret service would break down, as it is through her [Holland] that almost all our best information is received”.[5]

German Espionage in the Netherlands

German intelligence (Nachrichtendienst) in 1914-1918 was directed from Wesel and Antwerp. Both the German army and navy sent agents from these bureaus into Holland. In Antwerp agents of different nationalities, including Dutch, were trained for assignments in the Netherlands. They were taught to write in invisible ink, to cross the Dutch-Belgian border, to contact Vertrauensmänner in Holland and to recruit people who could travel to and from Britain inconspicuously. German interests focused on information on the British Army, the export of strategically important goods to Germany, and the Netherlands itself as a possible future battleground. For information on Britain, the Germans had to send agents to England, either via Rotterdam or Flushing, or recruit Dutch employees of ferryboats or commercial travellers. The execution of two Dutchmen in the Tower of London in 1915 illustrates the risks involved for the agents.

The central figure in German espionage in Holland was the German consul in Rotterdam, Carl Richard Gneist (1868-1939). His diplomatic means of communication were regularly used to send information to Wesel and Antwerp. He compares more of less with Tinsley, as Maxse, Gneist’s counterpart in Rotterdam, was more involved in spreading British propaganda, in order to influence Dutch public opinion. The Germans seem to have given that task to their consul in Amsterdam, Carl Cremer (1858-1938), and to the cultural department of their legation in The Hague.

The main German activity was recruitment of informants, especially people who could travel to Allied countries. This was not unknown even to the Dutch public. Just as the press published about Tinsley’s, so Geist’s activities were also made public. Dutch newspapers reported on the bogus companies the Germans established in Rotterdam as cover for activities to get people to and from Britain: one of them situated only a few hundred yards away from Tinsley’s office. Rotterdam was of great importance for the Germans, as it was the main port for imports to the Ruhr area. Even before the war the German presence in Rotterdam had been substantial; from 1914 onward some resident Germans offered their services for espionage. Other Germans joined them, disguised either as merchants, shipbrokers, and salesmen in tea or tobacco or as newspaper correspondents.

An important relationship existed in 1917-1918 between the aforementioned Amsterdam police detective Broekhoff and the German spy from the Antwerp office Leonard Balet (1879-1965), who was of Dutch origin. They met regularly and shared important information, so GS III knew many details on subjects that were important for the Germans in Antwerp. The Dutch used channels like this to convince the Germans about their sincere wish to stay neutral. The German modus operandi differed from the British at least in four ways. More than the British the Abwehr sent police officials to Holland, for counterespionage. These officers were in contact with the Dutch police, but the Dutch refused the close cooperation the Germans requested.

The second difference had to do with German activities to investigate Dutch defence, motivated by the German fear of a British attack on the Dutch coast. From 1916 onwards, new military operations against the Netherlands were planned, the so-called Fall K (Küste), to be executed in case the British would try to master the Dutch coastline and Antwerp. This had to be prevented at all costs. While this plan was being developed in 1916-1917, the Germans were actively accumulating military information on the Dutch defences and the notoriously difficult Dutch waterways and polders, especially in the Scheldt estuary. It is conceivable that Eugen Steiner’s arrival in Amsterdam should be seen in this light. The Germans used their information network in The Hague and made ample use of bribed Dutchmen, among them serving military, to get detailed information on the coastal province of Zeeland. It was agent Balet who told Broekhoff about these German military preparations.

To “assist” the Dutch in coastal defence, the Germans in 1918 even invited Dutch officers to inspect the coastal defence works in Flanders. These were shown in detail and the blueprints were handed over, so the Dutch could use them to extend their coastal defences along their North Sea coast, which indeed they did intend to do. The end of the war prevented any works from actually being built.

The third typically German approach was the abduction from neutral Dutch territory of opponents of the German government. In July 1916 the Germans kidnapped a French and a Belgian spy from the southernmost tip of the Netherlands. The Frenchman was Emile Fauquenot (1897-1966), a young Parisian student who had family connections in the Liège area in Belgium. He had been sent by the French secret service to Maastricht to gather information from Belgium before sending it via Rotterdam or Flushing to Folkstone, the hub of Allied intelligence gathering. In the summer of 1916 the Germans rounded up the Belgian network led from Maastricht, and German agents lured Fauquenot to the Dutch-Belgian border. He was dragged across the border and imprisoned. Dutch authorities protested against this abduction by German police from Dutch territory and demanded some sort of compensation. Negotiations were still dragging on when the war ended.

In December 1917 the German revolutionary and journalist Carl Minster (1873-1942) was abducted at the Dutch-German frontier, 30 km east from Maastricht. This case was even more controversial than Fauquenot’s. German authorities suspected that Minster, who had fled to Holland to avoid German military service, received information from opposition circles inside Germany, which he sent to the Allies via Holland. With British and private Dutch funding, Minster published in Amsterdam his left-wing weekly Der Kampf (The Struggle). His kidnapping caused uproar in the Dutch press, which may have helped delay his trial in Germany long enough for the war to end. At the end of 1918 he returned to Holland for a short stay, before resuming his revolutionary activities in Germany.[6]

Dutch Responses to Foreign Espionage Activities

GS IIIs policy was not to interact directly with representatives of the belligerents, but only via intermediaries. The intermediaries were the municipal police, the military police and state detectives who continuously shadowed the comings and goings of many foreign agents. The system of keeping in touch with British and German agents gave the Dutch a reasonably good insight into the workings of foreign spies on Dutch territory. By giving foreign agents some leeway to ply their trade, but also by questioning them and preventing clashes between spies of different countries, the system worked two ways. Foreign agents collaborated with the Dutch authorities, who in return gave them some freedom as long as Dutch interests were not violated. Moreover, via the agents the Dutch let the belligerent states know time and time again that maintaining neutrality was their one and only goal. In addition two liaison officers were appointed to report on the court cases and other developments relating to espionage within the Ministry of Justice. GS III’s idea was to get as much information out of the agents as possible, while leaving them in peace as long as they did not disturb public order, endanger Dutch neutrality or entangle Dutch citizens in their activities. Dutch law had not foreseen a situation of long-term mobilisation in which foreign spies used Dutch territory for activities not directed directly against Holland but against other belligerents. The number of court cases remained low, and not all cases brought before a judge ended with a conviction. It was difficult to prove both that neutrality had actually been endangered and what the exact intentions of the accused had been.

The Dutch penal code contained three articles relevant to espionage, articles 98, 100 and 430. The first put a maximum of six years’ imprisonment on handing over state secrets to third parties by which the interest of the state or its allies could be harmed. Article 100 put a maximum of ten years’ imprisonment on actions that could implicate Holland in war. Article 430 set a maximum sentence of two months on the unauthorised drawing or measuring of military installations. Article 98 demanded criminal intent and proof that information had actually been handed over to a foreign power. In court this proved difficult to establish. The same problem arose with article 100, which demanded evidence of criminal intent to create a situation from which war might follow. Article 430 did not mention photography and was vague on what could be considered objects of military interest. Moreover, the modest maximum penalty prevented temporary custody for suspects.

When the first cases were brought before a court, they resulted in acquittals because neither the intention to harm neutrality nor the actual fact of jeopardizing neutrality could be proven.[7] Another course of action proved more successful, but could not be considered a real alternative: in March 1915 a Dutch employee of the State Telegraph who had sold military information to the British, was convicted under article 363, which put a four-year maximum sentence on acceptance of money or services in exchange for dereliction of one’s duty.[8] From 1917 to 1919 eight other telegraphists were similarly prosecuted and convicted.[9] The sentences were relative mild, not exceeding one year. The longest sentence during the war years was three years for selling Dutch military information. The perpetrator was a Dutch soldier.

Another option was forced eviction from Holland based on the 1849 Law on Aliens. Article 12 of that law gave the possibility to evict somebody who was disturbing public peace and order.[10] At the local level the military authorities could evict people from the areas under martial law. This was done many times, after suspects had been charged for smuggling or espionage. The commander-in-chief, appalled by the behaviour of the foreign consuls, regularly stressed the need both to strengthen the laws against spying and to expand military rule over the entire country, but the government was not prepared to follow his far-reaching proposals.

The minister of justice did put forward some proposals to amend the penal code and adjust it to the fact a large number of foreign agents, who were in general not acting against the Netherlands, had to be monitored and kept within acceptable bounds. In 1914 the new article 103a had already proposed a six-year maximum sentence for handing over military information to a foreign power, with the intention of harming the interests of the Dutch state. Also, in the spring of 1915 a new article (100b) was proposed, which put a four-year sentence on delivering information to a belligerent state, while Holland itself was neutral. This information had to be damaging to the interests of the opponent(s) of the belligerent. Neither proposal was ever implemented, but it is interesting that the government in its explanation mentioned that the general sense of justice demanded action against spying, even when Holland was neutral and even when international law was unclear on this. In daily practice GS III’s pragmatic solution prevailed and worked.


The belligerent powers had a pretty good insight into Dutch defensive military measures, partly furthered by the Dutch themselves to make clear they took their armed neutrality seriously. The Dutch authorities realised that the territory was mostly used to gather and transfer information related to the war effort, not to Dutch neutrality itself. For intelligence-gathering purposes the maintenance of Dutch neutrality was of great value to the belligerents themselves. The pragmatic Dutch approach, born out of inexperience and the limited policing means available suited the situation.

Wim Klinkert, University of Amsterdam

Section Editor: Samuël Kruizinga