By the 1860s, the overcrowding and poor sanitary conditions forced the government to look for a more suitable location and the Ferdowsi site was purchased.

[4] Most famous of all the historical events associated with the embassy is the great 'bast' (meaning sanctuary) of July/August 1906 when, during the constitutional struggle, some 12–16,000 Tehranis took sanctuary in the compound and by thus paralysing the life of the city, forced Muzaffar-ud-din Shah to issue his celebrated Farman of 5 August 1906 granting the people a constitution and National Assembly.

Heads of mission returned in November 1997 following the election of President Mohammad Khatami, who showed determination to pursue the establishment of a civil society and the rule of law, and to promote wider international understanding.

The protesters smashed windows, ransacked offices, set fire to government documents, and burned a British flag.

[11] In July 2013, it was announced that the UK would consider to open better relations with Iran "step-by-step" following the election of President Hassan Rouhani.

[12] 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.

[14] The embassy continued to be managed by a charge d'affaires until 2016, when the then-incumbent Nicholas Hopton was promoted to ambassador.

The sprawling tree-lined site, bordered by high walls, measures 200,000 square metres (49 acres) and houses British diplomats and their families.

[17] The Qajar monarchy gave the land for Gholhak Garden to the United Kingdom in the 19th century during the height of the British Empire for their ambassador to use as a summer residence.

Today, several British diplomats and their families as well as some Iranian embassy staff reside in the Gholhak complex.