Das Englandspiel or English Game, also called
Unternehmen Nordpol (Operation North Pole), was an enormous counter intelligence operation launched by the German Intelligence Organisation (Abwehr) during World War II. German forces captured Allied resistance agents operating in the Netherlands and used the agents' codes to fool the Allies into continuing to provide the agents with information and supplies. About fifty Allied agents were identified, captured, and executed.
Apprehended radio operators continued broadcasting encrypted messages, but without the required "Security Checks" that should have alerted the SOE that they had been compromised. Further, SOE's head of codes Leo Marks claims to have soon realised that unlike all other coded messages, the Dutch messages contained no errors which made them indecipherable. He reasoned that this was because they were not coded in the field, but by German cryptographers. Finally, he sent them a deliberate indecipherable of his own, which was replied to. He reasoned that no ordinary agent could have resurrected his message. However no action was taken.
When it became apparent that the penetration had been uncovered, Major Hermann Giskes sent the following message in clear to London on April 1, 1944:
To [the SOE section chiefs] Messrs Blunt, Bingham and Successors Ltd. You are trying to make business in Netherlands without our assistance. We think this rather unfair in view of our long and successful co-operation as your sole agent. But never mind whenever you will come to pay a visit to the Continent you may be assured that you will be received with the same care and result as all those who you sent us before. So long.
University of Science Music and Culture (USMC) class of 71 and 72 ~ Extraneous (AKA Mziln)