Despite the presence of an angry crowd of demonstrators outside, the British ambassador could not take down the union flag at the embassy in August 1969 because it was Princess Anne's birthday, State papers released to the National Archives have revealed.
The incident took place on August 15th, when feelings were running high over events in Derry's Bogside and in Belfast. Five people were shot dead in the North the previous night, four of them by the security forces.
A confidential memo by an official in the Department of External (later Foreign) Affairs reports that he had received a phone call about lunchtime from the Labour TD Mr Michael O'Leary who was inside the embassy.
"He said that a number of demonstrators were outside the embassy in an ugly mood and wanted the British flag taken down. He had seen the ambassador who said that he was in a difficulty about taking down the flag as today was Princess Anne's birthday and the flag would be flown from all British embassies.
"According to Deputy O'Leary, he was not prepared to take down the flag unless requested to do so by the Department of External Affairs.
"Deputy O'Leary asked me to request the British ambassador to take down the flag in order to avoid trouble and damage to the embassy which would almost certainly ensue if the flag were not taken down."
In response, the Department informed Mr O'Leary that "in accordance with international practice we could not ask any embassy not to fly their flag especially on some sort of a national occasion".
Meanwhile, the Secretary of the Department of Justice, Mr Peter Berry, was contacted and he advised that "there were as many police as demonstrators at the embassy and he was satisfied with the course of action we proposed".
However, at 2.45 p.m. the ambassador, Sir Andrew Gilchrist, telephoned External Affairs to report that a number of demonstrators "had climbed up on the outside of the building, had taken down the British flag, burned it, and had replaced it by the Irish flag".
According to the official who took the call, the ambassador said the Garda Síochána were "incapable" and "unwilling" to do anything about the situation, although there were "about half as many demonstrators as there were gardaí".
"I asked the ambassador if he intended me to interpret his references to the gardaí as implying a criticism of them.
"He replied, somewhat testily, that this was not his intention: that he realised, in fact, that it would have been difficult for them to do anything."
The British embassy was then located on Dublin's Merrion Square. Three years later, in February 1972, the building was burnt down in the aftermath of the Bloody Sunday shootings in Derry.