> For years, I thought the CIA was the prime mover of the coup, but I was wrong.
I think the CIA was indeed the prime mover of the coup, at least according to the CIA's official history. Derbyshire, the person who was in charge of SIS's Iran branch, came up with the idea of a coup, but the Brits had not the capacity to pull it off and so they asked the CIA for help. The whole operation was very well documented by the declassified report entitled "CIA Clandestine Service History, Overthrow of Premier Mossadeq of Iran, November 1952-August 1953", which is downloadable from