Shocking photos taken in the capital shows a huge crowd of revellers cheering as two flags were set alight.
Another two flags of Israel, one of Iran’s fiercest rivals, were also set on fire during the celebrations last weekend.
President Hassan Rouhani had called for a “year of unity” as Iran celebrated 39 years since the Islamic revolution after weeks of protests last month.
However, tensions in the country remain high and last weekend’s confrontation with Israel, which saw an Israeli fighter jet downed during a firefight over Syria, have done little to calm tensions.
The UK and Iran have had a long and troubled history, despite slightly warming relations in recent years following the election of moderate Rouhani as president.
Britain earned the nickname ‘Wily Old Fox’ as they helped carve up and hand out parts of then-Persia to Russia and Afghanistan during the 19th century.
The UK also gained control of all Iranian oil during the early 20th century, as well as a heavy influence over its army and treasury.
During the mid-20th century Britain and America supported a coup, snuffing out a democratically elected-government and introducing the unelected and dictatorial Shah.
And after he was deposed in the Islamic Revolution, the UK and USA then supported Sadam Hussein’s Iraq during the Iran-Iraq war, which saw more the one million Iranians lose their life.
For this Britain gained a new nickname, ‘Little Satan’, and were reviled more than any other country but the USA, called ‘Great Satan’.
The year following the 1979 revolution terrorists took over the Iranian embassy in London, holding a number of hostages before they were rescued by the SAS.
Britain responded by closing its embassy in Tehran for eight years – the first of several closures and re-openings during the latter-decades of the 20th century.
In 2001 Jack Straw became the first major UK politician to visit Tehran since the revolution, with Prince Charles visiting an earthquake-devastated region three years later.
However, relations again deteriorated when Britain imposed sanctions on Iran, who responded with fury. A group of students attacked the Tehran embassy in 2011, injuring three British officials, and the UK recalled its diplomatic staff and closed the Iranian embassy in London.
Both embassies have since re-opened and, at a diplomatic level at least, relations are again warming.
Source » express