Ambassador Kyaw Zwar Minn – who broke ranks with his country’s military junta last month – told CNN that he tried to access the embassy for several hours on Wednesday but was unable to enter.
Several of his employees were still in the building and were not allowed outside, he also said.
Phone calls to the embassy went unanswered and emails were returned.
Kyaw Zwar Minn, the British ambassador, issued a statement last month calling for the release of Suu Kyi and pledging to keep the embassy open, following an appeal with British Foreign Secretary Dominic Raab.
Raab said in a tweet at the time that he spoke to the ambassador and “praised his courage and patriotism to stand up for the good”.
The military responded by recalling him. “Since he did not behave in accordance with the given responsibilities, an order [is issued] to summon him and return him to the State Department, ”MRTV reported.
A livestream from Facebook on Wednesday showed several people expressing their support for the British Ambassador to Myanmar and expressing their confusion about the day’s events.
About 50 people also gathered outside the embassy building in Mayfair, an exclusive part of central London.
Agents from London’s Metropolitan Police were also on the scene, warning people to spread for violating coronavirus restrictions.
Most who have since rallied have been dispersed over the evening, but CNN has seen at least four police vans full of officers park near the Myanmar embassy.
London’s Metropolitan Police told CNN in a statement, “We are aware of a protest outside the Myanmar embassy in Mayfair, London. Public order officers are in attendance. There are no arrests.”
In a statement to CNN, the British Foreign and Commonwealth Office said it was “seeking more information following an incident at the Myanmar embassy in London.”
Myanmar’s military leaders unsuccessfully tried to sack another diplomat in March after UN Ambassador Kyaw Moe Tun called on members of the international community to use “whatever means necessary” to help restore the country’s civilian leadership.
However, he refused to resign, a decision backed by the UN.
Myanmar’s military spokesman Major General Zaw Min Tun has said the junta plans to hold new elections after a year of emergency.
Helen Regan contributed to this report.