The Office of Strategic Services was the vast American espionage organisation created by President Franklin Roosevelt in the Second World War and directly modelled on Britain’s intelligence services.

The OSS, which evolved into the Central Intelligence Agency (CIA) after the war, was created virtually from scratch in 1942, and swiftly evolved into a wide intelligence-gathering network, employing soldiers, lawyers, actors, sportsmen, academics and many others.

The full extent of the spy network will be revealed when the National Archives in Washington declassifies the names and personnel files of around 24,000 people who worked for the secret organisation between 1942 and 1945.

The OSS was the brainchild of Major General William “Wild Bill” Donovan, a New York lawyer and First World War veteran. In 1942, President Roosevelt ordered Donovan to draw up a blueprint for an entirely new intelligence service, modelled on the Secret Intelligence Service, MI6, and the Special Operations Executive.

Donovan consulted British spy-masters, including Ian Fleming, the author of the James Bond books, then an officer in Naval Intelligence, and the OSS was established by presidential order in June 1942. The primary function of the OSS was to gather information on enemy nations, carry out sabotage operations, and distribute propaganda to undermine the enemy.

Perhaps the strangest aspect of the new spy organisation was that no such thing existed before the war. Hitherto, America had gathered intelligence without overall direction or control. A fledgling code-breaking department within the State Department was closed down in 1929 on the grounds that “gentlemen don’t read each other’s mail”.

From such fastidious beginnings would emerge the CIA, an organisation not noted for gentlemanly methods.

Under Wild Bill Donovan, the OSS swiftly developed into a highly effective intelligence tool: gathering enemy plans, running agents and double agents, decoding messages, fomenting resistance, sapping enemy morale, conducting unconventional war and generally carrying out the full gamut of skulduggery that was wartime espionage.

But not all of the OSS activities proved to be good long-term investments. Among other operations, the OSS helped to train resistance movement such as Mao’s Red Army and the Viet Minh in French Indochina as tools to undermine Axis control in those areas.

The OSS was terminated on September 20, 1945, and its functions later assumed by the CIA.

Times Recommends

• Thousands of Tamils dying in 'welfare camp'
• Jackson 'rebuilt his nose before he died'
• Renewed Iran protests crushed by militia