The coup of 1953 changed the course of Iranian history. The USA - with British help - overthrew a nationalist prime minister and installed the Shah in power.
In 2010, Alan Johnston heard archive recordings of the CIA officer who played a part and spoke to Hedayat Matine-Daftary, the grandson of Mohammed Mossadeq, the deposed prime minister.
(Photo: crowds of people protest against the Iran coup in 1953. Credit: Getty Images)