Not so long ago, Britain was held in such low esteem in Iran that it was simply dismissed as the "little Satan". So far as the ayatollahs were concerned, the real enemy was America, the "great Satan", whose love of liberty and free market capitalism was thought to pose the gravest threat to the Islamic revolution's survival.
It was for this reason that the American embassy, rather than the British, was occupied by the Revolutionary Guards in Tehran soon after Ayatollah Khomeini seized power in 1979, and its 66 staff held hostage. The expansive grounds of Britain's diplomatic mission, which hosted Winston Churchill during the Tehran conference in 1943, were briefly occupied by the Guards during Iran's revolutionary turmoil, but then evacuated because the mullahs did not regard Britain as being of sufficient importance to hold it to ransom.
But 30 years later it seems all that has changed as it is now Britain, rather than America, that finds itself on the receiving end of the ayatollahs' ire. After initiating last week's tit-for-tat diplomatic expulsions, which saw two middle-ranking British diplomats expelled from Tehran for allegedly fomenting anti-government demonstrations, the Iranian authorities have arrested a further nine British embassy employees. Although some of the workers have since been released, there has been no let-up in the regime's anti-British rhetoric.
After Ayatollah Ali Khamenei, Iran's supreme leader, launched the initial anti-British tirade by denouncing Britain as the "most treacherous" of the regime's enemies, there has been no shortage of prominent Iranians lining up to denounce the "devious" British. At the heart of the dispute is Tehran's insistence that British spies have been responsible for stirring up the worst street protests Iran has experienced since 1979. Manouchehr Mottaki, Iran's Foreign Minister, even went so far as to accuse Britain of sending planes filled with agents to Iran "with special intelligence and security ambitions".
In the past, Iran's purges and executions have been directed against those accused of spying for America or Israel. But the emergence of Britain as the mullahs' latest bête noire suggests Anglo-Iranian relations are about to undergo another period of intense strain.
To some extent the decision by the Iranian regime to direct its anger against Britain is a consequence of President Barack Obama's impact on the international scene. During the Bush administration, when Washington regarded Iran as part of the "axis of evil" of rogue states, Tehran had no hesitation about denouncing Washington's attempts to undermine the Islamic revolution.But Mr Obama's arrival at the White House has signalled a new start in Washington's approach to Iran, with the American President offering to conduct face-to-face talks with Tehran if the regime agrees to "unclench its fist".
Similarly, Mr Obama's Cairo speech earlier this month, in which he spoke of a new beginning between the US and Muslims around the world, has already made a deep impression on the Middle East. The result of Lebanon's general election, in which the moderate, pro-Western parties defeated the radical, Iran-backed Hizbollah Islamic group, has been attributed to the "Obama effect".
Although the hardline conservatives who run Iran would be loath to admit it, Tehran is also starting to feel the pressure from the Obama administration, particularly over its nuclear programme. Soon Washington will seek to establish a dialogue with Iran to resolve the nuclear crisis, and the Iranian government is well aware that it will be far harder to say "no" to Mr Obama than it was to spurn Mr Bush.
The removal of America as the focal point of Iran's anti-Western rhetoric makes Britain, which remains America's closest ally in Europe, a ready-made replacement. And whereas the hostility between Iran and the US only goes back three decades – to Khomeini's revolution, to be precise – the climate of mutual suspicion, recrimination and antipathy that exists between London and Tehran dates back centuries.
Britain established trading ties with the kingdom of Persia in the early 17th century, but relations between London and Tehran encountered their first set-back in the early 19th century, when the Persians were forced to concede territory to Russia under the terms of the Treaty of Gulistan, negotiated by the British diplomat Sir Gore Ouseley. This was regarded as a humiliation by many Iranians, and the perception of Britain as a "wily fox" quickly took root within the country's political classes.
Relations further soured when Britain arbitrarily set Iran's borders with India in the 1860s, but matters came to a head in 1872 when the then shah awarded Baron Paul Julius von Reuter, the founder of Reuters news agency, a monopoly over virtually all of Iran's economic and financial resources. Lord Curzon, the British Foreign Secretary at the time, described the "Reuter Concession", as it became known, as "the most complete and extraordinary surrender of the entire industrial resources of a kingdom into foreign hands that has probably ever been dreamt of, much less accomplished, in history".
Public outrage at the deal ultimately led to the constitutional revolution at the turn of the 20th century, which resulted in Iran adapting the principles of democratic government. But Britain's reputation for deviousness was further enhanced in the 1950s when British intelligence officers helped Kermit Roosevelt, the CIA station chief in Tehran, to overthrow the democratically elected government of Mohammed Mossadeq in 1953.
Mossadeq, in common with many Iranians, wanted a more equitable distribution of Iran's new oil wealth, which was still overseen by the British-controlled Anglo-Iranian Oil Company. But when Mossadeq attempted to nationalise the oil business and depose the shah, the British and American governments authorised a counter-coup that restored the shah to power.
Of all the acts of imperial perfidy conducted by the British, it is the overthrow of Mossadeq's government that remains most deeply embedded in the Iranian psyche, to the extent that, in accusing Britain of stirring unrest over the recent presidential elections, the Iranian regime has no difficulty convincing its people of British complicity.
Nor is Britain entirely blameless of charges that it is actively supporting attempts to overthrow the Iranian government. The recently expanded BBC Persian Service, which is funded by the Foreign Office and has now added a television channel to supplement its radio broadcasts,
has contributed to suspicions in Tehran that the British Government
is plotting to undermine the Islamic republic.
The BBC insists it is doing nothing more than offering public service broadcasts to its international audiences, but the fact that the BBC was recently accused of broadcasting coded messages that indirectly led to the Shah's overthrow 30 years ago has done little to allay suspicions.
The presence in London of the People's Mujahideen Organisation, the main Iranian dissident group that regularly launches attacks against Iran, also adds to Tehran's sense of paranoia. At one point Britain tried to reassure Iran by placing the dissidents on its proscribed list of terror groups, but this failed after a successful appeal in Brussels.
Add to this the lead role Britain has played in enforcing UN economic sanctions against Iran – billions of dollars of Iranian assets are said to have been seized in London – and it is easy to see why the mullahs have been quick to make Britain a scapegoat for their own difficulties. And with Iran's newly re-elected president Mahmoud Ahmadinejad insisting that there will be no fundamental change in his position on the nuclear issue, Anglo-Iranian relations are likely to deteriorate even further in the months to come.
