The demonstrators attacked the embassy compound with stones and pelted eggs and tomatoes at the building. Several embassy windows were shattered.
British and American flags were set on fire during the demonstration. A car tyre was also set alight and hurled towards the main gate of the embassy
Chants of Death to England and Death to America could be heard as the protestors waved banners reading, America, England, shame on you and your tricks, Nuclear technology is our legitimate right, and Uranium enrichment must begin in Natanz.
Protestors also called for the closure of the British embassy and the expulsion of the British ambassador Richard Dalton. Several Persian-language websites run by allies of hard-line President Mahmoud Ahmadinejad reported earlier this week that Iran was considering the recall of its ambassador to London and the expulsion of the British envoy.
There were also threatening chants directed at United States President George W. Bush. We swear to the blood of the martyrs, we will kill you, Bush, protestors yelled.
The United Kingdom had drafted Saturdays IAEA resolution which demanded that the Islamic Republic suspend its sensitive nuclear work or be referred to the United Nations Security Council.
The Bassij – affiliated to the Islamic Revolutionary Guards Corps – are hard-line Islamist vigilantes loyal to Supreme Leader Ayatollah Ali Khamenei and were recently given new powers to act as the countrys back-up police force.
Previous demonstrations by the Bassij outside the British embassy in Tehran resulted in attacks on the embassy compound.
Two explosions were heard near the British embassy on Sunday evening, though there was no immediate confirmation of the cause of the blasts.
In mid-August, hundreds of hard-line members of the Islamist organisation rallied outside the embassy, chanting death to England and demanding that British spies leave the country. They pelted the compound with rocks and tomatoes, trampled on American and Israeli flags, and set them on fire.
They were protesting against what they described as Londons conspiratorial role in securing a resolution in August critical of Irans nuclear activities by the IAEA board.