Britain's ambassador to Iran has revealed how seven of his staff were seized by protesters during the terrifying attack on UK compounds in Tehran.

Dominick Chilcott said some workers and their relatives were sent to the embassy's residential complex in the north of the city before the protests for their safety, but ended up being taken by demonstrators who surged through security.

He said staff were in a worse predicament than those in the main embassy building because they had gone there thinking it was a "place of safety", so when the attack happened it was "more of a surprise".

Mr Chilcott, who was only appointed to the role in October, told how protesters rampaged through the main embassy, "vandalising" one of Britain's "great historic" buildings. A painting of the Queen was removed, while portraits of previous monarchs were mutilated and fires started in a "spiteful" attack.

He said he and his staff had "no idea how it was going to end" but were eventually escorted out by police who told them to "lie low".

He said there was a "chain of command" that linked to the hardline student protesters to the Iranian government and claimed there was a belief that "bashing the Brits" did a "lot of good".

He added: "Iran is not the sort of country where spontaneously a demonstration congregates then attacks a foreign embassy. That sort of activity is only done with the acquiescence and support of the state."

It comes as the last Iranian diplomats left the UK following the Government's decision to close their London base in response to the attacks. On Wednesday, Foreign Secretary William Hague gave Iran 48 hours to remove all staff from UK soil in response to the "outrageous and indefensible" incident.

A Foreign Office spokesman said: "I can confirm that, earlier this afternoon, all diplomatic staff of the Iranian Embassy in London took off from Heathrow airport."

The latest developments were discussed by Prime Minister David Cameron during talks in Paris, where he thanked President Nicolas Sarkozy for his country's help. France was one of several European nations to withdraw ambassadors from Tehran in reaction to the looting of the building, which was widely condemned internationally.