The success of the British Commandos during World War II prompted U.S. President Franklin D. Roosevelt to authorize the creation of an intelligence service modeled after the British Secret Intelligence Service (MI6), and Special Operations Executive. This led to the creation of the Office of Strategic Services (OSS). On September 20, 1945, shortly after the end of World War II, Harry S. Truman signed an executive order dissolving the OSS, and by October 1945 its functions had been divided between the Departments of State and War. The division lasted only a few months. The first public mention of the "Central Intelligence Agency" appeared on a command-restructuring proposal presented by Jim Forrestal and Arthur Radford to the U.S. Senate Military Affairs Committee at the end of 1945. Despite opposition from the military establishment, the United States Department of State and the Federal Bureau of Investigation (FBI), Truman established the National Intelligence Authority in January 1946, which was the direct predecessor of the CIA. Its operational extension was known as the Central Intelligence Group (CIG)
Who's secret intelligence service was the US's modeled after? (If the question is unanswerable, say "unanswerable")
British