Reading up on this it appears to me many of Germany's spy operations inside the UK were pretty quickly shutdown. I investigated a half dozen spies who were captured by the end of 1942.

Other's I was considering who were not arrested during the war...

  • Horst Kopkow - An SS Officer, responsible for counter-sabotage and counterespionage. During the war, Kopkow's agents captured several hundred Soviet and British agents. Kopkow was informed and consulted over every capture, although he never left his headquarters in Berlin. One of his major efforts was the destruction of Red Orchestra and Rote Drei espionage networks. Security police also captured agents of MI6 and SOE. Kopkow authorized several hundred orders to execute the agents. This continued to the end of the war in 1945. His superiors rewarded him with medals.
  • Harold Cole - A Brit, who worked with the French Resistance. Turned over about 30 pages of notes on the F.R. to German Military Intelligence. "Described as the worst traitor of the war". Was active throughout the war.
  • Elyesa Bazna(Cicero) - Employed as a valet to the British ambassador to neutral Turkey from 1939. Passed on important information about many of the Allied leaders' conferences, including the Moscow, Tehran and Cairo Conferences. The details for the Tehran Conference were important for Operation Long Jump, the unsuccessful plot to kill Franklin D. Roosevelt, Joseph Stalin, and Winston Churchill. He had also conveyed a document that carried the highest security restriction (BIGOT list) about Operation Overlord (the code name for the Invasion of Normandy in June 1944). Stopped selling information to the Germans by the end of February 1944 and left the embassy within a month or so. After the war, Bazna was questioned for war crimes, but he was never charged with espionage.

Other than Elyesa Bazna who stopped selling information early 1944, these candidates seem to be pretty low level. More tactical than strategically damaging. They all did damage, but I was wondering. Who was the Greatest German Spy of WWII? To make this more specific I'll limit it to contemporary WWII German perspective. Is their a consensus among historians?

Per Denis de Bernardy suggestion, looking for someone who reported intelligence which reached Nazi Germany and not simple a high ranking official in the Nazi intelligence. Most successful German spy means successful in collecting information valued by German Intelligence, not valued just due to his rank and leadership.

  • 5
    You might want to make a distinction between sources (e.g. Cole or Brazna), spies (who recruit and work sources), and spy bosses (e.g. Kopkow, who oversee spies). Else you're really comparing apples to oranges. Aug 25, 2019 at 8:08
  • 1
    The "Red orchestra" (Rote Kapelle) were not an "espionage network". They were anti-fascist resistance fighters.
    – fdb
    Aug 25, 2019 at 23:02
  • Does Otto Skorzeny count as a spy for this question?
    – nick012000
    Aug 26, 2019 at 14:26
  • 3
    Wouldn't the most successful spy be, by definition, someone whose name you would simply never learn? Anyone who was captured or later exposed couldn't have been all that great at being a spy. The most successful ones probably enjoyed a long, relaxing, anonymous retirement and were forgotten by history. Aug 26, 2019 at 15:39

1 Answer 1


From the "contemporary German perspective", the answer is doubtless "Alaric", Juan Pujol García, known to the British as "Garbo". He was paid a total of US$340,000 and awarded the Iron Cross, second class, in July 1944 for his contributions to the war effort. He operated a network that grew to 27 sub-agents in all parts of the UK, communicating via post to Lisbon at first, and later by radio.

Unfortunately for the Germans, they never realised that he was a double agent. He'd gone into business for himself, selling the Germans "intelligence" that he simply invented. He had an extraordinary imagination, and they found him quite convincing, in spite of his lack of knowledge of the UK. He'd wanted to work for the British, but they were not interested at first. Later they took him up, moved him to the UK, and provided information for him to send. The sub-agents were all fictional.

There was a structural weakness in the operations of the Abwehr during WWII. It had bases in neutral countries, whose operations were not confined to those countries, so they were in competition with each other. Alaric was handled by the Madrid base: his messages were all sent there. This gave his handlers no motive to suspect that the intelligence was false: discovering that would be very bad for their comfortable positions in Spain, with the Eastern Front and the U-Boats always short of officers. They would, in fact, do better if they promoted the work of their agents, and thus their own, in the continuous competition of the Nazi state.

This was why the Abwehr were so readily deceived by the Double-Cross System operated by the British. They essentially stopped sending agents to the UK after 1942, because they were confident in their sources. The British were operating all of the remaining agents, and the messages they sent by post or via radio to their handlers were often re-sent to Abwehr HQ by radio, using the Enigma machine, providing chosen-plaintext attacks on the Enigma.

The regular reading of Abwehr Enigma enabled the British to be sure that they had all German agents in the UK under control, allowing them much greater scope in misleading the Abwehr. This contributed significantly to the success of the invasion of Normandy, as they were able to convince the Abwehr via "reports from agents" that there were large forces in Kent and Sussex ready to invade in the area of Calais. This compelled the Germans to keep part of their forces in the Calais area, making them unavailable for defending Normandy.

All this amply justified MI5's policy of capturing and turning agents sent by the Germans, as opposed to the FBI's policy of high-profile trials and executions. Most of the agents listed in the question were not sent by the Germans, but people who decided to spy for the Germans of their own accord. Without training, they weren't very successful.

Sources: Masterman The Double-Cross System and Hesketh Operation Fortitude.

  • 13
    It might be worth noting that Enigma enabled British Intelligence to verify that Double Cross had achieved 100% coverage, and thus to be much more aggressive in its deceptions. Aug 25, 2019 at 15:16
  • 8
    @VladimirF If the question uses "contemporary" to mean "WWII-era," he was thought at the time to be very successful.
    – cpast
    Aug 25, 2019 at 16:41
  • 18
    @VladimirF As cpast says, the Germans at the time thought Alaric was a marvellous agent. "Who was the German agent in Great Britain who actually did the most good for the German cause?" is a different question, because the Germans were so thoroughly deceived. Aug 25, 2019 at 16:53
  • 7
    @VladimirF it's a very easy mistake to make. The word is naturally ambiguous in English, and it really hinges on one word in the post to make it clear that the question means "contemporary to the war" and not "today's perspective".
    – hobbs
    Aug 26, 2019 at 1:11
  • 3
    @VictorS The weakness comes from the competitiveness that was part of Nazi ideology, and the dishonesty that comes from unrestrained competition in a political system based on propaganda. An good intelligence system needs to be able to look at the information it's getting with a very cool head and ask "is this too good to be true?" Oddly enough, the WWII Italians, who were the least formidable in combat of the Axis powers, were the hardest to fool with fake intelligence. Aug 26, 2019 at 8:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.