Juan Pujol García deceived the Third Reich to shield the Allied invasion

By Constance Bell · August 9, 2026

German intelligence was blinded by a phantom spy network while the Security Service used a clinical ledger to verify that the enemy believed every strategic lie.

The file's catalogue entry records a table. It is a clinical instrument of verification, a side-by-side comparison between the "ISOS product"—intelligence gathered from intercepted signals—and the "Security Service deception material." The purpose of this ledger, found under catalogue reference KV 2/42, was to determine if the lies being fed to the Third Reich were actually being believed.

At the center of this feedback loop was Juan Pujol García. Known to the public record as a Spanish spy who operated as a double agent for the United Kingdom, García was given the codename Garbo by the British. He spent the war creating a phantom world for his German handlers, managing a non-existent spy network they called "Arabal." For the Security Service, Garbo was not just an asset; he was a delivery system for strategic misinformation.

Operation Starkey

According to the catalogue description for KV 2/42, the table specifically tracks Garbo's messages as they implemented OPERATION STARKEY and OPERATION OVERLORD. This was the administrative side of the Great Lie. While the world remembers the D-Day landings as a triumph of military logistics and bravery, the records remind us that it was also a triumph of managed perception.

By comparing the deception material sent by Garbo with the ISOS intercepts, the Security Service could see, in near real-time, how the German intelligence apparatus processed the fiction. If Garbo sent a report about phantom divisions in the Pas-de-Calais and the ISOS intercepts showed the Germans moving troops to counter that specific threat, the table confirmed the success of the deception. It was a closed loop of state-sponsored fabrication, where the truth was measured by the quality of the enemy's mistake.

Letter and WT

Garbo’s work was not limited to a single medium. The National Archives hold a series of related files—KV 2/63, KV 2/65, KV 2/66, and KV 2/67—which the catalogue descriptions identify as containing copies of communications by "letter and WT" (wireless telegraphy).

These records represent the raw materials of the deception: the actual correspondence between a man living a double life and a government that owned his narrative. The use of wireless telegraphy added a layer of technical authenticity to Garbo's persona, making his fictitious network appear more robust and professional to the Germans. These files, categorized under "Double Agent Operations," show the exhaustive nature of the effort. Every letter and every burst of radio traffic was a calculated brick in a wall of misinformation designed to shield the actual Allied invasion force.

Other Channels

While the double-cross system—the process of turning enemy agents—was a primary tool for the Security Service, it was not the only one. Catalogue reference KV 4/429 describes a separate set of papers concerning "policy and procedure regarding channels for deception other than special agents."

The description for KV 4/429 notes that these papers deal with the "deception of the German Intelligence Service by means other than the double-cross system," specifically through the "spreading of false" information. This suggests a broader strategy of environmental manipulation. While Garbo provided the specific, trusted voice of a high-level asset, the Security Service was simultaneously seeding the landscape with other, less personal forms of noise.

This tiered approach to lying—combining the trusted word of a double agent like García with broader, anonymous channels of misinformation—created a redundant system of deception. If one channel failed, another was there to reinforce the fiction. The state did not rely on a single point of failure; it built an entire ecosystem of falsehoods.

The records left in the KV series provide a window into the coldness of this process. We see the names of operations and the codenames of agents, but the catalogue descriptions highlight the process above all else: the comparison, the policy, the procedure. We are left with the image of officers in London staring at a table, checking boxes to see if the Germans had fallen for the bait.

Whether the Germans ever suspected the duality of the "Arabal" network or if they were simply blinded by their own expectations remains a question for the historians. The archives merely confirm that the British government was keeping a meticulous ledger of the deception.