Operatiën en Inlichtingen
The Dutch Stay-Behind Organisation during the Cold War
In the Netherlands, a secret
stay-behind organisation (SBO) was formed
just after WWII had ended, in 1946 or 1947. For many years,
was known as O&I, the abbreviation of Operatiën en Inlichtingen
(Operations and Intelligence) 1
although it was also known under other names.
Nevertheless, the organisation is often (wrongly) identified as
after the Italian SBO branch.
Although O&I had a good relationship with
and with sister organisations in other countries,
like Germany, Belgium and the UK, is was the only fully autonomous and
fully self-controlled stay-behind organisation in Europe.
It was neither controlled by NATO,
nor by any other foreign agency, including
and the CIA
Each agent had a set of manuals, coded information about agents, transmission
schedules, code material, financial means (e.g. money and gold), a radio
transmitter and receiver (spy radio set)
and sometimes a weapon and ammunition.
These items were usually stored inside one or more containers
that were hidden by the agent, e.g. in the attic or burried in the garden.
Some of this material was also stored in other places, known as caches,
both in The Netherlands and abroad.
In total, between 100 and 200 agents were involved in the Dutch network,
which consisted of a staff and field agents .
The staff of ± 20 people was involved with organisational tasks,
administration and instruction and training
of field agents. In the event of a war with the
Warsaw Pact countries,
the staff would be moved to a safe base in the UK, North America
The field agents were divided into organisers and
operators. An organiser was specialised in reconnaissance,
forging ID papers, sabotage, information gathering, psychologic warfare,
organising illegal press, etc. In the event of a war, the organiser
would autonomously built his own clandestine network.
Each organiser was assigned an operator
who maintained contact with the staff abroad.
The operator was specialised in operating the radio equipment,
coding and decoding messages,
sending these messages in Morse Code and
preventing interception and direction finding.
Initially, the agents would operate in pairs (organiser and operator),
but later, when automatic radio stations were deployed, the single-agent
concept was introduced .
In 1990, after stories about subversive actions by the Italian
'GLADIO' had reached the press, Dutch Prime Minister Ruud Lubbers
confirmed the existence of a Dutch
SBO. He also stated that,
unlike the other SBOs, the Dutch organisation was autonomous and was
not controlled by NATO,
or the CIA.
Less than two years later
he saw himself forced to dismantle the organisation.
➤ Full history of the Dutch SBO
Although the official name for the Dutch SBO was O&I,
it is sometimes referred to as I&O,
even by people who worked for the organisation 
and by government officials .
In 1985, the name was changed to A&B,
but the old names O&I / I&O also remained in use.
In the scope of this page we will use O&I.
Over the years, the Dutch stay-behind organisation used a variety of
radio sets, ranging from wartime valve-based British spy radio sets,
to fully automatic digital long-range radio stations with built-in
Below is an overview of all radio sets that are known to have been
used in this context in The Netherlands.
Please note that not all O&I personnel will have used
all of these radios in an operational context.
The use of the above sets has been confirmed.
The Type 3 Mark II, commonly known as the B2, is arguably the most
well-known spy radio set of World War II. It was developed in 1942 and was
used throughout the war by many agents that were dropped over occupied
territory. It is heavy and is housed in an 'unobtrusive' travel suitcase.
After WWII, the B2 was used for several years in some European countries
(e.g. the Netherlands)
by the Stay-Behind Organisation (SBO) .
➤ More information
The Type A Mark III, commonly known as the A3, was much smaller than
the B2, but was suitable for short to mid-range communication only.
Like the B2 is was a left-over from WWII, but unlike the B2, it was much
The radio was usually installed inside a small children's evacuee suitcase,
such as the ones that were issued during WWII in the UK
➤ More information
The Mark VII, commonly known as the Paraset, was developed
in the UK around 1943, and was used during WWII by agents that were
dropped over occupied territory. It is either housed in a metal or a
wooden enclosure, and required the valves (tubes) to be removed before
The Paraset was arguably one of the most dangerous radio sets produced
by the British. In reception, the signal from its local
oscillator was strong enough for the Germans to locate the agent by
means of Radio Direction Finding (RDF).
No further information at present.
Like the British B2, the American SSTR-1 was housed in a common
unobtrusive travel suitcase. During WWII, some SSTR-1 units had been
used in the Netherlands and in Belgium.
After the war, some SSTR-1 units were used by the Dutch SBO, but
not to the same extent as the British B2. In the Netherlands,
the SSTR-1 was known as TR-1 .
No further information at present.
The S-Phone was a short-range full-duplex UHF radio system,
developed in 1942 in the UK for use by the SOE
and by resistance fighters, during droppings and landings
on occupied territory.
As the radio only worked in the line-of-sight (LOS), it was
relatively safe against interception. In the early years of
the Dutch SBO, it was used during infiltration and exfiltration
➤ More information
Another left-over from WWII that was used by the Dutch SBO, is the
British Mk.119. It was developed in late 1940 by
at Hanslope Park (UK), and was also used by Special Forces (SF) and by
the British Diplomatic Wireless Service (DWS) for communication with the
British Embassies overseas.
The radio was available in two versions: a three-piece solution in which
transmitter, receiver and power supply unit (PSU) were each housed in a
separate container, and a single-piece variant in a wooden case,
shown in the image on the
The B2, A2 and Mk.119 were the last wartime long-range radio sets that
were used by the Dutch SBO, before moving to newly developed post-war
equipment from Dutch, German and American manufacturers.
➤ More information
After using a variety of Army Surplus (mainly from Belgian surplus sales)
during the first years of the Dutch SBO, the ZO-47 was the first
spy radio set to be developed in The Netherlands.
In 1946 the order was given by
Colonel J. Somer
of GS III C (foreign intelligence)
to Philips/NSF for a total of NLG 20,000
ZO-47 is the abbreviation of Zendontvanger
(transceiver) 1947 .
By early 1948, about 100 ZO-47 units had been delivered to the Dutch
Messages were sent manually in Morse Code
(using a morse key) via a limited number of frequencies.
The compact radio station consisted of three same-size units:
a transmitter, a receiver and a power supply unit (PSU) that were
connected together by means of short cables. It could easily be
concealed in a watertight container, allowing the set to be stored for
extended periods of time (e.g. in an attic or burried in the garden).
Some sets were also stored in the so-called caches.
A cache is a secret hiding place, where large quantities of
supplies (e.g. weapons, ammunition, money and radio equipment) are stored
for the event of war. During the 1980s, two caches were discovered
by the public in The Netherlands,
but in each case no further information about them
was revealed. In 1992 however, a large cache was found in a house at
at the Parkstraat in Utrecht (Netherlands). It contained weapons,
explosives and also two complete ZO-47 radio stations.
Due to the type and age of the discovered weapons and the radio sets,
it seems reasonable to assume that it was a 'forgotten cache'
from the early years of the Dutch stay-behind organisation .
Despite the desire of many museums and private collectors to obtain
the discovered ZO-47 radio sets, the District Attorney ordered their
destruction. Fortunately, one unit was saved from demolition and was
donated to the Dutch Signals Museum
(Museum Verbindingsdienst) were
it was put on public display.
The design of the ZO-47 was improved at least once, probably in the late
1940s or the early 1950s, and the improved device was designated ZO-47/01.
➤ More about the ZO-47
The RT-3 was valve-based spy radio set that was developed in the US
shortly after WWII, probably around 1948. It was intended for use by the
CIA for foreign clandestine operations and by stay-behind organisations.
It was known in the US as RS-1 (CIA)
and by its army designator GRC-109.
It is not exactly clear when the RS-1 was used in The Netherlands and how
many units were deployed. Furthermore it is not entirely certain that the
Dutch designator for the set was indeed RT-3. According to information found
at the Dutch Signals Museum (Museum Verbindingsdienst) ,
it was named after the transmitter (RT-3) that is part of this highly
The RS-1, as it was officially called in the US, consists of three modules:
a transmitter (RT-3), a receiver (RR-2) and a power supply unit,
each packet in a watertight aluminium container.
The RT-3/RS-1 was used in The Netherlands as an intermediate solution
between the ZO-47 and the later RT-6 (RS-6) which is featured below.
It is quite possible that the RT-3 was used in parallel with the ZO-47
and the RS-6, until all units were eventually replaced by the RS-6.
➤ More about the RS-1 (RT-3)
In the early 1950s, suitable alternative spy radio sets became
available from countries like the US, the UK and Germany. As a result,
it was no longer necessary for the Dutch to develop their own equipment,
and it was decided to replace the ZO-47 units by the American RS-6 radio set.
The RS-6 was developed by Motorola in the US in 1951 and was initially
intended for exclusive use by the CIA. It was based on the earlier RS-1.
A few years later, the Strategic Air Command (SAC) started ordering the
RS-6 for use aboard aircrafts during 'special' (clandestine) missions.
From that moment on, the RS-6 became noticed by other services and
was used as a clandestine radio station (spy radio set) for stay-behind
organisations. In The Netherlands it was used by O&I
from the mid-1950s onwards. It consisted of a transmitter, a receiver,
and a power supply.
A fourth box, the so called filter unit, was used to connect the other
three units together.
In the early spy radio sets, an electro-mechanical vibrator
was commonly used to convert battery voltages (e.g. 6V) to the
much higer voltages needed for the valves (e.g. 130V).
Such vibrators were not very reliable, especially when the
radios were stored for extended periods of time.
In 1960, O&I asked for a solution and it was
decided to replace the vibrator with an electronic transistor-based
alternative. This resulted in a modified version of the RS-6, in
which the so-called power inverter was built inside the filter
unit. Futhermore, some units were modified by replacing the
typical American circular connectors by standard 9-pin sub-D
➤ More about the Dutch version of the RS-6
➤ More about the standard RS-6
In the late 1960s and the early 1970s, the older radio sets were
gradually replaced by the German
SP-15 spy radio station.
This station consisted of a crystal-operated transmitter, a very sensitive
receiver and one or more power supply units. It was in use for a
number of years already with the German Intellicence Agency (BND),
the German Special Forces (SF) and the German stay-behind.
At the heart of the SP-15 radio station was an
FS-7 valve-based transmitter,
made by Pfitzner, and the fully transistorized
that was made by Wandel & Goltermann. Both units were developed
in Germany in the late 1950s.
In the mid-1970s, the Dutch FS-7 transmitters were modified for use
in combination with a synthesizer that was developed by RACAL in the UK,
especially for the Dutch O&I organisation. From then on, the station was
known as FSS-7. The image on the right shows the
Dutch SP-15 setup,
complete with its watertight container.
In the early 1980s, the Allied Clandestine Committee, or ACC —
attached to NATO headquarters SHAPE in Mons (Belgium) — approved the
development of a pan-European communication system for all
European stay-behind organisations,
including some neutral countries such as Sweden and Switzerland.
The new clandestine radio station
was developed by manufacturer
AEG Telefunken in
München (Germany) —
in close cooperation with
MI6 in the UK — under the codename HARPOON.
As the Dutch O&I urgently needed a replacement for the ageing FSS-7,
and the new HARPOON radio sets were not expected any time soon,
the RACAL PRM-4150 (TITHE) was choosen as an intermediate solution.
It was already in use
with the British Armed Forces, the Diplomatic Wireless Service (DWS) and
stay-behind, and had a proven track record. It became known
as the DZO-81; Data Zend-Ontvanger
(data transceiver) 1981.
It consisted of a transmitter, a receiver, an automatic antenna tuner
and a coding device, mounted together in a Samsonite briefcase.
The DZO-81 no longer required the ability to send and receive messages
in morse code, as the coding unit could automatically send and receive
messages at pre-determinded time schedules. As a result, separate radio
operators were no longer required and the organisation adopted the
single-agent concept, in which the intelligence agent
(i.e. the organiser) also operated the radio.
Unfortunately, not many DZO-81 units have survived. Following the discoveries
of a number of caches in the Netherlands in the 1980, the Dutch Government
saw itself forced to dismantle the organisation and ordered destruction of
the remaining equipment. Most of the equipment was subsequently collected
and destroyed at Hoogovens (blast furnaces, now: Tata Steel)
in IJmuiden (Netherlands).
Fortunately though, the officer responsible for the destruction kept back
one of each model, and donated it to the Dutch Signals Museum
➤ More about the DZO-81 (PRM-4150)
By the late 1980s, the new HARPOON system,
developed by AEG Telefunken,
was ready to replace all existing clandestine radio sets in Europe.
By this time, the Berlin Wall
had already fallen (1989) and the
was about to collapse (1991). As a result, HARPOON would be the final
The official designator of the HARPOON system was
FS-5000, but in the
Netherlands it was known as AZO-90, short for: Automatische
Zender-Ontvanger (automatic transceiver) 1990.
The AEG-Telefunken designator was SY-5000.
In total, The Netherlands received 110 HARPOON units between 1988 and 1990.
The initial five units were received in November 1988. Two of these
were used for training operators. The next shipment of 35 units was received
in December 1988 .
The remaining 70 were received in the 2nd half of 1989 and in the 1st quarter
In 1990, the first international Long Range (LOR) tests were carried out,
and the results with the FS-5000 sets were promising. By March 1991, all sets
ordered by the various countries had been delivered.
As the Dutch organisation had already developed a computer system
and software for secure message processing — back in 1989 —
the Netherlands became the first country with a fully automated FS-5000
store-and-forward message handling system .
The LOR tests and the software deveopment took place at NEBAS,
the Dutch base station at Villa Maarheeze
in Wassenaar (near The Hague) where O&I had been located
since the beginning, under the cover of the
Dutch Foreign Intelligence Service
(Inlichtendienst Buitenland, or IDB).
In December 1991, NEBAS was moved to a more convenient location
with less public exposure in Utrecht
where a completely new building had been erected at the premisis of the
KMAR, the Royal Dutch Military Police, at Fort De Bilt.
Here they were able to install a large Log-Periodic antenna.
➤ More about the AZO-90 (FS-5000)
During WWII, The Netherlands had two independent intelligences agencies,
both of which operated from England under the authority of the Dutch
Government in exile:
- BI - Bureau Inlichtingen
This was the Intelligence Bureau.
It was controlled by the Dutch Government in
exile (London) and was similar in nature to the British MI6.
The BI was tasked with gathering military, political and economic
intelligence, mainly on Dutch soil.
- BBO - Bureau Bijzondere Opdrachten
This was the Special Operations Bureau.
It operated directly under (and was largely
controlled by) the British
Special Operations Executive (SOE).
The BBO's task was to set up a resistance organisation
and execute sabotage operations in occupied Netherlands.
BI was led by
Colonel Jan Marginus Somer
who had already developed plans for a secret section of the
Dutch General Staff just before WWII under the name
GS III C. In the event of war, the main tasks of the section
would be active intelligence
gathering (espionage) and stay-behind. By 1939, Somer had successfully
initiated GS III C, but it was too late to be of much use during the war.
Once the war was over, Somer rejuventated his GS III C section, albeit in
a less ambitious form than he had anticipated. The section was actually the
post-war variant of the wartime BI.
For the stay-behind division of his section, he needed communication equipment.
After having used a variety of Army Surplus (mainly from Belgian stores),
he managed to secure a budget of NLG 20,000 (EUR 9100), for the development of the first (and only) Dutch spy radio set:
The order for the development was given by Somer in 1946 to Philips/NSF.
Development took most of 1947 and by the end of that year the radio was
ready for its first field test. In early 1948, the first batch of 100 units
was delivered to the BI. By that time, Somer had already been appointed
head of intelligence in the Dutch Indies and was succeeded by
J.J.L. baron van Lynden. This intelligence section (i.e. the former BI)
would later become known as the I-service.
➤ More about Jan Marginus Somer
➤ More about the ZO-47 radio set
Bureau Bijzondere Opdrachten
Around the same time (1946), a former secret agent of the wartime BBO,
had developed his own plans for a stay-behind organisation.
With the lessons learned from WWII, for example the now famous Englandspiel
that had cost more than 54 lives, he was convinced that The Netherlands
needed a strong and well-organised resistance in the event of another war.
When he conveyed his plans to the Dutch Royal Commander-in-Chief Prins Bernhard,
the latter put him in contact with Louis Einthoven, the newly appointed
head of the Dutch Bureau of National Security
Einthoven was easily convinced and allowed him to setup an effective
operations unit which was actually the post-war varant of the wartime
The new organisation did not officially exist and became the direct
responsibility of the Dutch Prime Minister. This secret operations
section would later become known as the O-service.
➤ More about Henk Veeneklaas
During the first years, the O and I service operated independently
from each other, without each of them knowing about the other's
existence. The I-service was controlled by the Ministry of Defense
and reported directly to the Minister.
The O-service on the other hand, fell under the
Ministry of General Affairs and reported only to the the Prime Minister.
Around 1948, the SBOs in various European countries
formed the Western Union Clandestine Committee (WUCC) in which thoughts
were exchanged about the theoretical structure of a stay behind organisation.
was established in 1949, it took over the military aspects of
the Western Union as well as (in 1951) the tasks of the WUCC.
At NATO's headquarters – known as SHAPE – a Special Projects Branch (SPB)
was established, which was tasked with Unorthodox Warfare (UW).
During peace time, the so-called Clandestine
Planning Committee (CPC) would form the link between the SPB and the
various SBOs. The CPC would later be renamed
Allied Clandestine Committee (ACC)
and eventually to Allied Coordination Committee (also abbreviated to ACC).
In 1961, the first attempts were made to merge the activities
of the O-service and the I-service. This plan met strong opposition
from the founder and initial leader of the O-service, Henk Veeneklaas.
He argued that the two services were too different to be merged.
In his opinion, the I-service was a military organisation
whilst the O-service was purely a civil one. In 1967, the problem
was solved by discharging the heads of both services and appointing
a new coordinator.
From this time onwards, the Dutch clandestine service was known as
O&I (sometimes called I&O by its members), with the two services
working independently, but under supervision of the coordinator.
The main office of the organisation was housed in villa Maarheeze
in Wassenaar (near The Hague) under the cover of the
Foreign Intelligence Service (IDB).
The former BI (by now the I-service) was housed here since May 1945.
The image on the right shows villa Maarheeze in later years (2014).
It is currently used as a high-profile office building and can be rented.
For emergency purposes, the agents carried a so-called
Green Card that warranted them from interference by the civil
or military police. If they were discovered, e.g. by the police whilst
'on duty', they were allowed to present the Green Card. The police officer
could then call a special telephone number in The Hague
to verify a password that was specified on a separate card.
O&I was able to carry out its duties more or less undisturbed throughout
its existence. Nevertheless, some of its caches (hidden storage
places with weapons, money and communications equipment) were discovered
over time. The following incidents reached the Dutch press:
1966Discovery of weapons cache in the Wieringermeerpolder.
1980Discovery of weapons cache near Heythuysen (Limburg).
1983Discovery of weapons cache near Rheden.
1992Discovery of weapons and communications equipment in a house in Utrecht.
There were other incidents that reached the press, such as the discovery
of a large amount of weapons with Dutch criminals Sam Klepper en John
Mieremet in Alkmaar (Netherlands) on 29 August 1991. According to some
newspapers, these weapons were robbed from a cache in The Hague (Scheveningse
Bosjes). In 1983/84 the robbery was discovered and reported to the police,
but it was decided not to take any further action. Although it was suggested
that the stay-behind network was involved in this criminal activity,
no proof to support this claim was ever found .
In 2007, the Dutch Minister of Defense confirmed to the Dutch Parliament that
the weapons cache had indeed been robbed but that
a recent investigation had revealed that the weapons found with the criminals
were of a different brand and/or model than those taken from the cache .
In 1985, after the discovery of the weapons caches near Heythuysen (1980)
and Rheden (1983), the organisation was reorganised. It was decided
that the caches would be cleared and would only be refilled when there
actually was a clear threat of war. In the meantime, the weapons and explosives
were under control of the Dutch Military Police (Koninklijke Marechaussee).
At the same time, the organisation was renamed to A en B (A and B),
with A being the former O (Operations) and B being the old I-branch
(Intelligence). Nevertheless, most people kept using the old name O&I.
In order to avoid confusion, the tasks of the two branches were
reconfirmed by (then) Prime Minister Ruud Lubbers as follows:
A-service (Operations)B-service (Intelligence)
- Psychological warfare
- Mental resistance of the population
- Intelligence gathering
(military, political, economic)
- Infiltration and exfiltration
of people and goods
Despite the various incidents with caches in the 1980s,
the existence of the organistion remained secret for a long time.
All that changed when in 1990 the Italian SBO 'GLADIO' started appearing
in the headlines.
Gladio was suspected of involvement with some ultra right-wing
incidents and terrorist attacks. As a result, (then) Italian Prime
Minister Guilio admitted on 3 August 1990 the existence of a secret SBO
– named Gladio – and revealed that it operated under NATO control.
The indicents raised international public awareness of the secret
organisations, and resulted in a series of public hearings and investigations
in countries like Germany, Belgium, Switzerland and The Netherlands.
On 13 November 1990, Dutch Prime Minister Ruud Lubbers publicly confirmed the
existence of a Dutch SBO, but emphasized that it was completely
independent and was not (and had never been) under control of
or any other foreign organisation.
After the fall of the Berlin Wall
in 1989 and the subsequent collapse
of the Soviet Union (USSR)
in 1991, the threat of a possible Soviet
invasion was no longer deemed realistic and the necessesity for a
secret stay behind organisation had more or less disappeared.
Meanwhile, in 1990, the new European
HARPOON radio system (AZO-90, FS-5000)
had become available and The Netherlands was the first country to
to have implemented a fully automated message handling system.
In 1991, it became evident that the existing premises in Wassenaar
attracted too much attention. In December of that year the Dutch base
station NEBAS was moved to a more convenient location at Fort de Bilt
Despite all this, Prime Minister Lubbers felt he had no other option than
to shut down the entire operation. In 1992, he sent a personal letter to
the agents of both services in which he thanked them for their
loyalty and insisted that any details remained secret.
Members of the A-service (the former 'O') also received a personal
letter from Prins Bernhard who said he had warm feelings for the
organisation and had followed them with great interest from 1942
until now (1992). The administrative closure took until 1994, but
once that was handled, the secret Dutch SBO was history.
The former members receive a small pension for their services.
Eye witness: Herman Schoemaker
Former stay-behind radio instructor, 15 December 2013
For obvious reasons, members of the network had to obtain strict
secrecy during the operational years of the organisation (1946-1992).
This continued after the network was dismantled in 1992. Although
this is now over 25 years ago, the network has not been declassified
by the authorities yet. Nevertheless some former members have
recently decided to break their code of silence.
An example of such a former agent is Herman Schoemaker from Soest
(Netherlands). He was a radio instructor of the Dutch stay-behind
and worked for the network from the early 1960s right until the
end in 1992.
In June 2013 he graduated at the University of Utrecht with his
paper about the Dutch stay-behind O&I .
On the last opening day of our
special exhibition Secret Communications,
in Duivendrecht (near Amsterdam) in November and December 2013,
we had the honour of meeting Schoemaker and listen to his
more than exiting Cold War stories.
To our surprise, he was accompanied by two other former agents
who were involved in the same type of work. Although one of them
was an old friend of Schoemaker, he only learned about his involvement
in the network when he accidently recognized his voice during a training.
Schoemaker was trained as a radio specialist and he in turn trained other
agents in the use of the various radio sets. During the early days
(i.e. in the early 1960s) this involved using
and the use of the FSS-7 (SP-15) spy radio set
and its burst encoders.
Especially the use of morse code, the transmission frequency schedules
and the use of the cryptographic code material,
required a long and intensive training, something that
was greatly reduced when the automatic DZO-81
and later the fully digital AZO-90 (FS-5000, HARPOON)
radio sets were introduced.
➤ Review of Herman Schoemaker's visit
The Dutch stay-behind organisation was commonly known as O&I, which was
the abbreviation of Operatiën en Inlichtingen (Operations and Intelligence).
The organisation was only known to the Prime Minister and on some occasions the
Minister of Defense. It was offcially part of the General Staff of the Dutch Army
and operated from Villa Maarheeze in Wassenaar (Netherlands), under the cover
of the Inlichtendienst Buitenland (IDB), the Foreign Intelligence Service.
At the height of the Cold War, the I-department counted some 200 people.
Between 20 and 30 of them were responsible for the organisational tasks,
the administration and training (the staff). In the event of a war, the
staff would be moved to a safe country. The rest were the agents that
would stay behind in the occupied country. The following 17 bureaus were known:
- Secretariaat en Transport (administration and transport)
- Lijnen, (escape routes from occupied Netherlands)
- Inlichtingen en Netwerken (intelligence and networks)
- Radioverbindingen (radio communication)
- Reproductie (reproduction)
- Radiotechniek (radio engineering)
- Inlichtenoperaties via de IDB (intelligence via Foreign Intelligence)
- Codezaken (coding issues)
- Veldveiligheid (field safety)
- Luchtfiltratie (infiltration and exfiltration via the air)
- Zeefiltratie (infiltration and exfiltration via the sea)
- Speciale netwerk (special network)
- Short-term netwerk (short-term network)
- Comptabiliteit (accountancy)
- Financiële netwerken (financial networks)
- Meteo netwerk (weather reports)
- Documentatie/falsificatie (counterfeit documents, micro-photography, etc.)
This part of the organisation was responsible for the operational field
work, such as sabotage, raids, liquidations, etc. In case of war, the
organisation had access to weapons and explosives that were stored in
hidden locations, the so-called caches. Approximately 40 such caches
were present in the Netherlands, but these were dismantled after
discoveries in 1980 (in Heythuysen) and 1983 (near Rheden).
Below is an attempt to create a timeline of events that are
related to the Dutch stay-behind organisation. For this timeline,
information is used from the sources listed below [1-6], but
in particular from the PIVOT report by Dick Engelen 
and the 2013 thesis of Herman Schoemaker  the latter of whom
was a radio instructor for the organisation for many years.
End of WWII
Plans for stay-behind organisation in The Netherlands.
Development of ZO-47 radio set
Philips/NSF develops the first clandestine radio sets
First 100 radio sets
The first radio sets are delivered early in 1948.
These are probably ZO-47 manufactured by Philips/NSF.
Founding of NATO.
4 April 1949.
Discovery of weapons cache in the Wieringermeerpolder.
Discovery of weapons cache in Heythuysen (Limburg).
Introduction of the DZO-81 transceiver.
Discovery of weapons cache near Rheden.
Weapons stolen from a cach near The Hague (Scheveningse Bosjes)
O&I renamed to A&B
Fully automatic radio system AZO-90 (Harpoon)
Fall of the Berlin Wall
Italian stay-behind, known as Gladio, uncovered
Dutch stay-behind uncovered
13 November 1990.
After questions in parliament, Dutch Prime Minister Ruud Lubbers confirms
the existence of a Dutch stay-behind organisation.
End of Warsaw Pact
The Warsaw Pact falls apart, which is effectively the end of the Cold War.
Move to new location
In December 1991, the organisation is moved from Wassenaar to Fort de Bilt,
near Utrecht. Here a large Log-Periodic antenna is erected.
Discovery of weapons and communications equipment in
an abandonned house at the Parkstraat in Utrecht.
Among the many weapons and ammunition found, were two
ZO-47 radio sets.
The Dutch stay-behind organisation O&I is officially dismantled by
Prime Minister Ruud Lubbers. In 1994, all administrative tasks have
been completed and the network is officially closed down.
- H.J. Bekker, Geschiedenis van de Sectie Algemene Zaken
History of the Section General Affairs (uncensored).
31 December 1981.
- Dr. D. Engelen, De Nederlandse stay behind-organisatie in de koude oorlog 1945-1992
Ministerie van Algemene Zaken, Ministerie van Defensie & Rijksarchiefdienst/PIVOT
The Netherlands, National Archives, Institutional Investigation (Dutch).
The Hague, 2005. ISBN 90-5909-0489.
- Geschiedenis van de Sectie Algemene Zaken, Hoofdstuk VI, Consolidatie
History of the Section General Affairs, Chapter 6, Consolidation. (Dutch)
Describing the period May 1970 - December 1981.
Dutch National Archives.
Top Secret. 1
- Geschiedenis van de Sectie Algemene Zaken, Hoofdstuk VII, Voortgang
History of the Section General Affairs, Chapter 7, Progress. (Dutch)
Describing the period December 1981 - May 1987.
Dutch National Archives.
Top Secret. 1
- Geschiedenis van de Sectie Algemene Zaken, Hoofdstuk VIII,
Van Stroomlijning tot Ofheffing
History of the Section General Affairs, Chapter 8,
From Streamlining to Dissolution. (Dutch)
Describing the period May 1987 - January 1994.
Dutch National Archives.
Top Secret. 1
- Herman Schoemaker, Een geheime organisatie in beeld
De Nederlandse stay-behind-organisatie, geheim, onafhankelijk en zelfstandig?
The Dutch stay-behind organisation, secret, independent and autonomous?
Thesis under supervision of Prof. Dr. Bob G.J. de Graaff,
Utrecht University. 7 June 2013.
- Frans Kluiters, personal correspondence.
- Wim Kramer, Mysterie in Utrecht
RAM Magazine 136, Oktober 1992. pp. 17-19. 2
- Wim Kramer, Mysterie in Utrecht na jaren opgelost
RAM Magazine 191, Oktober 1997. pp. 32-35. 2
- Museum Verbindingsdienst (Royal Dutch Signals Museum)
Retrieved February 2009.
- W. van Middelkoop, Antwoord op Kamervragen 2060725030 en 2060725260
Answers by the the Dutch Minister of Defense to questions raised by Dutch Parliament.
9 November 2007 (Dutch).
- Bart Olmer, Ex-instructeur onthult bestaan ondergrondse verzetsgroep...
Interview with Herman Schoemaker at the event of the presentation of his Thesis .
De Telegraaf (newspaper) 9 November 2013. p. TA1.
- H.J. Bekker, Geschiedenis van de Sectie Algemene Zaken
History of the Section General Affairs — uncensored version of .
31 December 1981.
Partly declassified and released in 2007 under the FOIA
Reproduced here by kind permission from the author Wim Kramer.
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