[3] Iran responded by approving a bill to downgrade its ties with the United Kingdom, including a requirement for both countries to withdraw their respective ambassadors.

The rally began quietly, but some participants stormed the building, breaking down the door, throwing around papers and replacing the British flag with an Iranian one.

[3] According to the British Ambassador to Iran Dominick Chilcott, protesters rampaged through the embassy building, destroying paintings and furniture, spraying graffiti, smashing windows and starting fires.

Foreign Secretary William Hague said the "irresponsible action" had put the safety of diplomats and their families at risk and caused extensive damage to embassy property.

[14] Iranian state media agencies and certain international news sources described the protests as a reaction of students against Britain's anti-Iran policies.

[15][16] The demonstrators themselves issued an official statement, declaring, "Our actions are a spontaneous reaction of revolutionary students and were not ordered by any state organ.

[3][15][16][18] Al Jazeera's correspondent in Tehran, Dorsa Jabbari, reported that the Iranian police and various ministries had prior knowledge of the protest, which was organised by the student arm of the Basij.

[22] Iran's Foreign Ministry expressed regret over the attack, calling it "unacceptable" and said that it happened "despite the efforts made by the Iranian Law Enforcement Police and reinforcement of the embassy guards".

[24] Subsequently, the Sultanate of Oman agreed to act as a protecting power, representing the interests of Iran through its embassy in London.

[27] In November 2013, Iran and the UK agreed to end the protecting power arrangements of Sweden and Oman and appointed non-resident charge d'affaires to conduct bilateral relations between London and Tehran.

[28] US Vice-President Joe Biden said he had no evidence the attack on the British embassy in Tehran was orchestrated by Iranian authorities, but it was another example of why the country was a "pariah".

[29] France, Germany, Italy, and the Netherlands recalled their ambassadors to discuss the diplomatic matter, with Austria stating they are considering a similar decision.

[34] Hungary declined to recall its Ambassador to Iran following a meeting of EU Foreign Ministers on 1 December, saying it would cripple normal day-to-day operations due to its limited staff.

However, a number of Iranian students and people protested against the reopening of the British embassy on Sunday morning in the presence of Foreign Secretary Phillip Hammond according to Fars News Agency.