Historic tidbit on Dutch sigint in the 1980s, from Richard Aldrich’s book GCHQ – The uncensored story Britain’s most secret intelligence agency (2010):

The idea of GCHQ teaming up with the Europeans was not a bad one. European sigint services such as those of the Norwegians, the Germans and the Dutch were highly professional, and had made many important contributions to Western intelligence down the years, not least during the Falklands War. They often displayed brilliant lateral thinking. When Soviet naval ships entered Dutch harbours in the 1980s, their hosts would often complain that the Soviet radar was interfering with local television broadcasts and insist on a snap technical inspection. The crafty Dutch used this opportunity to plant a small tracking device high up on the Soviet ships that was no more than the size of a brick. This tracking device was so successful that it became a standard technique across the Western secret services. Typically, a small group of British SBS personnel worked with SIS and GCHQ on similar tasks in the 1990s. [Footnote 17: Tomlinson, The Big Breach, p.77]

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