Minn was reportedly asked to leave the building by Myanmar's military attaché and was forced to spend the night sleeping in his car.
Why was the ambassador locked out?
Minn has criticised the military coup which began in Myanmar on February 1, calling for ousted leader Aung San Suu Kyi to be released by the military.
In March, Minn told the BBC that Myanmar was "divided" and could be at risk of civil war.
He insisted that his remarks were not intended as a betrayal of his country, saying he stood on “middle ground”.
The Myanmar military regime issued a statement saying Minn had been summoned home, but he stayed in London
Myanmar’s military attaché subsequently seized the embassy and refused to recognise Minn as the country’s representative.
On the morning of Thursday, April 8, a spokesperson for the ambassador urged the UK government not to recognise the ambassador newly appointed by the Myanmar military.
Minn has described the actions of the military as a “coup d’état in central London”.
Who has replaced the ambassador?
While Foreign Secretary Dominic Raab has condemned the "bullying actions” taken by the military, the UK has accepted the change at the embassy in line with protocol.
According to the Vienna Convention, which governs diplomatic relations, an ambassador’s job is terminated as soon as the host country they’re in has been informed.
After receiving such notification, the UK Foreign Office said it "must accept the decision taken by the Myanmar Government".
While the Foreign Office say they have received “no formal notification” of who is to replace Minn, Reuters has reported that deputy ambassador Chit Win has taken over as chargé d'affaires in London.
Why did the coup start?
Myanmar, also known as Burma, gained independence from Britain in 1948 and was ruled by the armed forces between 1962 and 2011, when a new government began to usher in a return to civilian rule.
In 2020, Aung San Suu Kyi, a former Nobel Peace Prize winner and leader of the National League for Democracy (NLD) secured a landslide victory in the government election.
The military, however, had backed the opposition party - who called for a ballot recount after the NLD victory and claimed widespread voter fraud.
In spite of the election commission finding no evidence of voter fraud, the military prevented the NLD taking power by staging a coup just before politicians were about to begin a new session of parliament.
The military have imprisoned Suu Kyi, who is being held at an unknown location and is facing several charges from the armed forces, including possessing illegal walkie-talkies and violating the country’s official secrets act.
Shortly after the coup, a protest movement emerged, with hundreds of thousands of people in Myanmar taking to the streets to protest against the military takeover.
The protests have led to violent clashes with police, with several anti-coup protesters killed and many more arrested.
Popular model and actor Paing Takhon has recently been arrested as part of a crackdown on artists and actors by the military.
The 24 year-old has millions of fans, and was active in protests offline and online.