
Britain reopened its embassy in Tehran on Sunday nearly four years after protesters ransacked the ambassador’s residence and burned the Union Jack.
In a signal of the most striking thaw in Western ties with Iran for over a decade, Foreign Secretary Philip Hammond watched the British flag being raised in the garden of the opulent 19th century building while the national anthem played.
"Today’s ceremony marks the end of one phase in the relationship between our two countries and the start of a new one - one that I believe offers the promise of better," he said.
The attack that forced the embassy to close was a low point in diplomacy between the two countries, he said, but the relationship had improved "step by step" since the election of Iranian President Hassan Rouhani in 2013.

Hammond said the nuclear deal that the Islamic Republic struck with six major world powers last month was also an important milestone.