<P> Until 1997 the only flag to fly from Buckingham Palace was the Royal Standard, the official flag of the reigning British sovereign, and only when the sovereign was in residence at the palace . Even in times of mourning, the Royal Standard would not fly at half mast . The only time a different flag would be flown from the Palace would be upon the death of the sovereign, when the flag of the next most senior member of the Royal Family present at the palace would be raised . In 1952, the Standard of Queen Elizabeth The Queen Mother was raised upon the death of King George VI because the new sovereign, Queen Elizabeth II, was in Kenya . </P> <P> The size of the flag is varied according to the importance of the event, with a normal - sized flag being used most of the time . On state or ceremonial occasions, such as the wedding of Prince William and Catherine Middleton, the Diamond Jubilee in 2012 and the sovereign's official birthday, a much larger flag is flown . </P> <P> This tradition changed in 1997, following the death of Diana, Princess of Wales, when the tabloid press reported alleged public outrage because the palace did not fly a flag at half mast . The Queen was at Balmoral Castle at the time, so there was no flag flying . In response to this display of public opinion, the Queen ordered a break with protocol and the Union Flag was flown at half mast over the Palace on the day of Diana's funeral . Since then, the Union Flag flies from the Palace when the Queen is not in residence, and has flown at half mast upon the deaths of members of the Royal Family, and other times of national mourning such as following the terrorist bombings in London on 7 July 2005, the death of former U.S. president Gerald Ford and the death of Margaret Thatcher on 8 April 2013 . </P> <P> Similar protocols are followed at different royal residences, depending on location and the member of the royal family in residence . Clarence House, for example, is the official London residence of the Prince of Wales, so flies his personal standard when he is in residence . Similarly, when the Queen Mother lived there it flew her personal standard . After her death in 2002, her standard was flown at half mast during the mourning period . </P>

When is the union jack flown at half mast