But that is the case with Coup 53, Taghi Amirani’s deep dish, sometimes breathtaking examination of the U.S.-British-instigated coup that brought down the democratically elected president of Iran, Mohammad Mosaddegh, in the summer of 1953, as the young shah waited in the wings.

“We still do not know who leaked this to the Observer originally, or why,” said film-maker Taghi Amirani this weekend, ahead of the release of his documentary, Coup 53.