William Hague, centre, the UK's foreign minister, gave the Iranian diplomats 48 hours to leave London [Reuters]

Iran's diplomats in London have flown home on Friday as a deadline loomed for their expulsion following the storming of the British embassy in Tehran on Sunday.

"I can confirm that, earlier this afternoon, all diplomatic staff of the Iranian embassy in London took off from Heathrow airport," said a British foreign office spokesman.

"They are returning to Iran in line with the foreign secretary's statement to parliament on Wednesday."

William Hague, the British foreign minister, told parliament on Wednesday that he had given Iran's diplomats 48 hours to close the embassy and leave the country after the attack on Britain's mission in Tehran on Tuesday.

The Iranian flag was still flying outside the Iranian embassy in west London ahead of the deadline but a stream of people could be seen carrying suitcases and boxes out of the premises.

A removals van was also parked outside a residential annexe to the building, while a British policeman was stationed at the door of the embassy.

Al Jazeera's Tim Friend reporting from London said: "The embassy is empty, and diplomats are on their way to Tehran."

Britain has also evacuated its diplomats from Iran and closed its embassy following the attack, which Hague said could not have happened without the Iranian regime's tacit consent.

The Tehran protest came after the Iranian parliament voted on Sunday to expel the British ambassador and reduce trade relations with Britain in retaliation for UK-led sanctions against Iran's banking sector.

Hundreds of students rampaged for hours through Britain's two diplomatic compounds in Tehran, tearing down the Union Jack flag , ripping up pictures of Queen Elizabeth II and trashing offices.

New sanctions

On Thursday, the European Union piled pressure on Iran following the attack, by beefing up sanctions over Tehran's nuclear programme and threatening to hit its oil and financial sector next.

Last week, the US, Canada and the UK announced new sanctions against Iran, including measures to restrict the activities of the Iranian central bank.

The UK said then it was severing all financial ties with Iran.

The move followed a report by the UN's nuclear watchdog (IAEA) that said Iran had carried out tests "relevant to the development of a nuclear device".

Iran denies the accusations, saying its nuclear programme is solely for peaceful purposes.

Fresh demonstrations took place in Iran on Friday in support of the storming of the British compounds, the official IRNA news agency reported.

After attending Friday prayers in Tehran University, worshippers flocked to central Enqelab (Revolution) Square, chanting "Death to Britain" and "(We) support the seizure of the second den of spies (the British embassy)."