In 1939, Germany sent many sabateurs to British shores, all of whom were well prepared for, and captured in hours. They were then presented with a simple choice; execution, or counter-espionage.
It didn't take long for them to choose counter-espionage. They were sent to the aptly named
double-cross commitee, who used them to gain
information on the whereabouts of troops, while giving them useless
information that Germany would recieve some days too late.
This commitee was never discovered or sspected by the Nazi espionage units, and many double-agents were receiving medals for thier work right up until the end of the war, when it was discovered by the surrendered German forces that thier celebrated agents had been working for Churchill, not Adolf Hitler