Extracts
10 September 2026

GARBO: MI5’s Most Extraordinary Double Agent

Inside the remarkable deception of GARBO, the double agent whose elaborate deception reached the highest levels of German intelligence.

GARBO: MI5’s Most Extraordinary Double Agent
Spanish double agent GARBO (Juan Pujol García) in disguise 1941. KV 2/70. The National Archives

One of the most successful spy networks of the Second World War was, for the most part, fiction. At its centre was Juan Pujol García, an unlikely double agent whose greatest weapon was his imagination. A Spanish chicken farmer recruited into MI5’s Double Cross System, Pujol invented agents who did not exist, sent reports about places he had never visited and gradually earned the trust of German intelligence. Operating under a codename borrowed from one of Hollywood’s most famous actresses of its golden age, his elaborate deception would reach all the way to Hitler, with extraordinary consequences for the Allied invasion of Normandy.

The extraordinary story of agent GARBO is just one of the remarkable cases revealed in The MI5 Archive: Official Secrets, the definitive visual record of the work carried out by Britain's Security Service from its origins to the modern day, told through original documents held by The National Archives which feature in the book. So, how did an ordinary Spaniard come to construct one of the most elaborate deceptions of the war?

This report [on the Garbo network] is…a record of the extent to which it is possible to deceive one’s opponent, through what is probably the oldest weapon of deception in war, the double agent. – Tómas Harris’s MI5 summary on the Garbo case, 1945

Juan Pujol García, codename GARBO, has been described as the greatest double agent of the Second World War. He was a Spaniard who, before the war, had run a chicken farm outside Barcelona. He was deeply opposed to Nazism and wanted to fight it using words rather than weapons.

In January 1941, Pujol approached the British embassy in Madrid offering to spy against the Germans. When they turned him down, he approached the Germans, adopting the guise of a fascist offering to spy against the British. This approach was also unsuccessful, but he persisted, and eventually he secured a positive response.

 

Spanish double agent GARBO (Juan Pujol García) in disguise 1941. KV 2/70. The National Archives

Pujol was given special ink for secret writing, cash and the codename Agent Arabel. He was instructed to get to Britain via Lisbon. When he arrived in the Portuguese capital, he again contacted the British, still hoping to be taken on as a spy for them - and was rejected once again. In July 1941 he sent a message to his German handler stating that he had safely arrived in Britain; in fact he was still in Lisbon and fabricating his reports, finding inspiration through the Lisbon public library and other resources. His 'intelligence' was full of errors. Referring to Glasgow, he wrote 'there are men here who would do anything for a litre of wine, an observation that would have bemused any local Glaswegian. Fortunately for Pujol, this seems to have escaped the notice of his German handlers.

In the winter of 1941, the codebreakers at the Government Code and Cypher School, Bletchley Park, were alarmed by messages between Madrid and Berlin which showed that the Germans were running a spy called Agent Arabel in Britain. They were also intrigued, however, by the large number of false claims Agent Arabel was making. Pujol continued to ask the British to recruit him and MI6 eventually realized the identity of the German agent sending false messages. Tar Robertson succeeded in securing Pujol as an agent to work for MI5, and he duly arrived in Plymouth in April 1942. He was given a cover job working for the BBC and given the codename GARBO after Greta Garbo, one of the greatest actors of Hollywood's golden era.

Pujol had a very fertile imagination, a quality recognized and greatly appreciated by his Spanish-speaking case officer, Tomas Harris. They formed a creative partnership, and by 1944 they had invented twenty-seven sub-agents, each with a convincing backstory. These fictional agents included a Welsh nationalist leading an equally fictitious group of fascists called the Brothers of the Aryan World Order, an Indian poet called Rags and an indiscreet US Army sergeant.

 

The Garcías' passport: MI5 brought Juan Pujol García to London with his wife Araceli. The National Archives

GARBO relayed the reports' he received from them, which were of course riddled with misinformation, to the Germans. His sub-agents had a strong presence, conveniently enough, in the south of England, particularly along the coast, and they sent a steady stream of reports on the build-up of Allied forces for the forthcoming invasion to be targeted on the Pas-de-Calais, part of an official deception strategy called Operation FORTITUDE. Just before the D-Day invasion was launched on 6 June 1944, GARBO was authorized to send advance notification of the landings to the Germans - carefully timed so that it would not make any military difference - in order to maintain his credibility.
GARBO continued his ruse after D-Day, maximizing the deception that the Normandy landings were just a distraction and the main landing was yet to come in the Pas-de-Calais. This proved a critical intervention on 9 June 1944.

The day before, the German High Command had authorized the mobilization of the formidable ist SS Panzer Division and Fifteenth Army to Normandy. This posed a huge danger to the Allies, whose newly established bridgehead was vulnerable. GARBO sent a long message in the early hours of 9 June warning the Germans not to send reinforcements to Normandy, as the decisive attack was very likely to take place in the Pas-de-Calais area. The report went all the way to Hitler, and the deployments of the German units were halted - they would await the real invasion in the Pas-de-Calais. It was a misguided belief that dominated German strategy for a remarkably long time. GARBO's actions kept the Allies bridgehead secure and saved countless lives.

Hitler maintained a seemingly unshakeable belief in GARBO. On 29 July, he received a message: The Führer has awarded the Iron Cross to you for your extraordinary merits.'

MI5 Archive: Official Secrets by Mark Dunton, principal contemporary records specialist at The National Archives

Extracts
Updated: September 10 2026

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