The final Iranian diplomats have been leaving Britain after the US and European Union imposed tougher sanctions on the country over its nuclear programme.
The Government had set a 2pm deadline for staff to leave, after an attack on the British embassy in Tehran on Tuesday.
A group of 20 protesters gathered outside the central London building to demonstrate against the Iranian regime.
They shouted “terrorists, terrorists, must go, must go” and said they were at the embassy to say goodbye to diplomats who represented the “dictator regime” in Iran.
On Thursday night the US Senate and EU foreign ministers agreed tighter sanctions on Iranian companies and individuals as part of a concerted effort to get Tehran to halt its nuclear programme.
When our new ambassador arrived in October, he was greeted with a Molotov cocktail over the wall.
Foreign Secretary William Hague
However, the EU ministers, meeting in Brussels, stopped short of imposing an embargo on Iranian oil.
Britain’s Foreign Secretary William Hague said the pressure on Iran should be stepped up.
Before the agreement, he had spoken of the need for “peaceful, legitimate, economic pressure, particularly to increase the isolation of the Iranian financial sector”.
He was backed by German counterpart Guido Westerwelle who said the aim was “to dry up Iran’s financial sources”.
The EU’s foreign policy chief, Baroness Ashton, said additional measures against Tehran would “make it clear to Iran that we are very serious”.
The measures are primarily a response to a report suggesting Iran may be seeking to develop nuclear weapons – something officials there deny.
But it also follows the ransacking of the British Embassy in Tehran which spurred the UK Government to shut the Iranian embassy in London and order all diplomats to leave the country.
Mr Hague said the attack – ostensibly by anti-West protesters – was backed by the Iranian regime and was in breach of the Vienna Convention.
The demonstrators smashed windows, set cars on fire and burnt Union flags as they ransacked the embassy building.
Baroness Ashton said an attack on the UK was considered an act against the whole of the EU. Mr Hague said Tehran should be “ashamed”.
He added: “If any country makes it impossible for us to operate on their soil, they cannot expect to have a functioning embassy here.
“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.”
The Foreign Secretary said he had been impressed by the “great and emphatic support” the UK had received from other European countries.
He also confirmed the tough action had been largely provoked by nuclear concerns, not the storming of the embassy.
“Our long-term concern is, of course, the nuclear programme,” he said.
In November, the International Atomic Energy Agency said Iran must provide further reassurance over whether it is seeking to develop nuclear weapons.
Germany, France and the Netherlands recalled their ambassadors for discussions over their own future relations and Italy indicated that it could follow suit.
Former foreign secretary David Miliband told Sky News Iran might be “exasperating, difficult… destabilising the rest of the region” but military action would be unjustified.
If Iran develops nuclear weapons it would be unacceptable but they are at least two years away from this, he said on Boulton and Co.
The Iranians appear to be saying: “You freeze our banks, we’ll heat up your embassies.”
Read Tim Marshall’s blog on Iran
Mr Miliband said “ingenious diplomacy” was key to stopping the situation escalating to war.
He also warned against allowing British concerns regarding the embassy attack to become muddled with the wider nuclear issue and “played into a drum-beat of war”.
The latest escalation of already-terse relations between the UK and Iran came after the UK severed all financial ties with Iranian banks in response to mounting fears over the country’s nuclear ambitions.
It was part of a wider international effort by the US and Canada to put pressure on the Islamic republic after the latest expert assessment increased fears the regime was seeking to develop nuclear weapons.
Iran responded by passing legislation downgrading diplomatic ties with Britain, which was swiftly followed by the attack on the embassy.
The Iranian foreign minister has apologised for the incident.
:: EU governments have also agreed to increase the pressure on Syria, adding 11 entities and 12 people to its sanctions list.