It's a weird irony that Iranians know the history of Anglo-Persian relations better than the Brits. When the newly installed Ministry of Islamic Guidance asked Harvey Morris, Reuters' man in post-revolutionary Iran, for a history of his news agency, he asked his London office to send him a biography of Baron von Reuter – and was appalled to discover the founder of the world's greatest news agency had built Persia's railways at an immense profit. "How can I show this to the ministry?" he shouted. "It turns out that the Baron was worse than the fucking Shah!" Of which, of course, the ministry was well aware.

Britain staged a joint invasion of Iran with Soviet forces when the Shah's predecessor got a bit too close to the Nazis in World War Two and then helped the Americans overthrow the democratically elected Mohammed Mossadegh in 1953 after he nationalised Britain's oil possessions in the country.

This was not a myth but a real, down-to-earth conspiracy. The CIA called it Operation Ajax; the Brits wisely kept their ambitions in check by calling it Operation Boot. MI6's agent in Tehran was Colonel Monty Woodhouse, previously our Special Operations Executive man inside German-occupied Greece. I knew "Monty" well – we co-operated together when I investigated the grim wartime career of ex-UN Secretary General Kurt Waldheim – and he was a ruthless man. Woodhouse brought weapons into Iran for a still non-existent "resistance" movement and he eagerly supported the CIA's project to fund the "bazaaris" of Tehran to stage demonstrations (in which, of course, hundreds, perhaps thousands, died) to overthrow Mossadegh.

They were successful. Mossadegh was arrested – by an officer assiduously done to death in the 1979 revolution – and the young Shah returned in triumph to impose his rule, reinforced by his faithful SAVAK secret police whose torture of women regime opponents was duly filmed and – according to the great Egyptian journalist Mohamed Hassanein Heikal – circulated by CIA officers to America's allies around the world as a "teaching" manual. How dare the Iranians remember all this?

The mass of US secret documents found after the American embassy was sacked following the Iranian revolution proved to the Iranians not only Washington's attempts to subvert the new order of Ayatollah Khomeini but the continued partnership of the American and British intelligence services.

The British ambassador, almost to the end, remained convinced that the Shah, though deeply flawed, would survive. And British governments have continued to rage about the supposedly terrorist nature of the Iranian government. Tony Blair – even at the official inquiry into the Iraq war – started raving about the necessity of standing up to Iranian aggression.