Foreign Secretary William Hague also said the British Embassy in Tehran had been closed and all staff evacuated following the attack on Tuesday by a crowd that broke through gates, ransacked offices and burned British flags in a protest over sanctions imposed by Britain on the Tehran government.
Iran said Britain’s decision to close the Iranian embassy in London on Wednesday was “hasty” and that it would lead to further retaliation, state TV reported, quoting a government spokesman.
“The foreign ministry spokesman ... described the move as ... hasty and added that naturally the government of the Islamic Republic of Iran would take further appropriate action regarding the issue,” the news reporter said.
It was the most violent incident so far as relations between the two countries steadily deteriorate due to Iran’s wider dispute with the West over its nuclear program.
On top of its ban on British financial institutions dealing with Iran and its central bank last week, Britain has called for further measures and a diplomatic source said London would now support a ban on oil imports from the Islamic Republic.
Hague said Iranian ambassadors across the European Union had been summoned to receive strong protests over the incident. But Britain stopped short of severing ties with Iran completely.
“The Iranian charge (d’affaires) in London is being informed now that we require the immediate closure of the Iranian embassy in London and that all Iranian diplomatic staff must leave the United Kingdom within the next 48 hours,” Hague told parliament.
“We have now closed the British embassy in Tehran. We have decided to evacuate all our staff and as of the last few minutes, the last of our UK-based staff have now left Iran.”
It was the worst crisis between Britain and Iran since full diplomatic relations were restored in 1999, 10 years after Ayatollah Ruhollah Khomeini’s fatwa to kill author Salman Rushdie for his book “The Satanic Verses.”
Hague said it was “fanciful” to think the Iranian authorities could not have protected the British embassy, or that the assault could have taken place without “some degree of regime consent.”
“This does not amount to the severing of diplomatic relations in their entirety. It is action that reduces our relations with Iran to the lowest level consistent with the maintenance of diplomatic relations,” he added.
British Prime Minister David Cameron chaired meetings of the government’s crisis committee on Tuesday night and again on Wednesday morning to decide London’s response.
But mindful of the 1979 seizure of the US embassy in Tehran, when radical students held 52 Americans hostage for 444 days, Britain waited till all its two dozen diplomatic staff and dependents had left the country to announce its move.
“It’s rock bottom as far as Anglo-Iranian relations are concerned,” said Ali Ansari, director of the Institute for Iranian Studies at St. Andrews University in Scotland. “The Iranians have a mountain to climb. I don’t think they fully understand how difficult it is for them now.”
Negotiations on Iran’s nuclear program were now “dead,” he said. “What you are moving into is a period of containment and quarantine. I don’t think we are into a military confrontation, but we are into a period of containment and they (the West) are going to try and tighten the noose.”
The attack also exposes widening rifts within Iran’s ruling elite over how to deal with the increased international pressure as sanctions take their toll on the already stagnant economy.
The protest appeared to be a move by the conservatives who dominate parliament to force President Mahmoud Ahmadinejad to heed their demand to expel the British ambassador.
Ahmadinejad and his ministers have shown no willingness to compromise on their refusal to halt Iran’s nuclear work but have sought to keep talks open to limit what sanctions are imposed.
The West believes the program is aimed at building a nuclear weapon, a charge Tehran strongly denies.
“This incident was planned by elements who are not opposed per se to negotiations but want to stop them merely because of their own petty political struggles,” said Trita Parsi, a US-based expert on Western-Iranian relations.
“The push to get the UK ambassador out came from parliament which is headed by Ali Larijani,” Parsi said. “When Larijani was chief nuclear negotiator Ahmadinejad carried out a similar campaign against negotiations.”
Conservative newspapers trumpeted the embassy seizure.
The daily Vatan-e Emrouz declared “Fox’s den seized,” referring to Britain’s nickname “the old fox” which reflects a widely held view in Iran that London still wields great power behind the scenes in Iranian and international affairs.
While Iranian police at first did not stop the protesters storming the embassy gates, they later fired teargas to disperse them and freed six Britons held by demonstrators.
Iran’s Foreign Ministry expressed its regret for the “unacceptable behavior of few demonstrators.”
The protesters hit back, saying they had been “seeking to answer to the plots and malevolence of this old fox” and the Foreign Ministry should not sacrifice “the goals of the nation for diplomatic and political relations.”
“We expected the police to be on the side of the students instead of confronting them,” said a statement by a group calling itself the Islamic community of Tehran universities.
Britain imposed sanctions on the Iran central bank last week after a report by the UN’s International Atomic Energy Agency suggested Iran may have worked on developing a nuclear arsenal.
Iran, the world’s fifth biggest oil exporter, says it only wants nuclear technology to generate electricity.
Britain has not backed a ban on Iranian oil imports, but that could now change, the diplomatic source told Reuters, and London will likely back a call by France to do just that and impose “sanctions on a scale that would paralyze the regime.”
The United States, which cut diplomatic relations with Iran after its embassy was stormed in 1979, has not bought Iranian oil since the 1990s, but has not taken any measures against Iran’s central bank. That would cripple Iran’s economy as it would not be able to process payments for its vital oil exports.
