 Complete the following phrase:  There was some controversy in the United Kingdom in 1997 following the death of Diana, Princess of Wales, over the fact that no flag was flown at half-mast at Buckingham Palace. Customarily the only flag to fly from Buckingham Palace had been the Royal Standard when the sovereign was in residence at the Palace or, exceptionally, after the death of the sovereign, the flag of the next senior member of the Royal Family would be raised, if the new sovereign were not present; otherwise, no flag would fly. In response to public outcry, Queen Elizabeth II ordered a break with protocol, replacing the Royal Standard with the Union Flag at half mast as soon as she left the Palace to attend the Princesss funeral at Westminster Abbey. The Royal Standard was again flown at full hoist on her return to the Palace. 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, such as Princess Margaret and the Queen Mother in 2002 and Prince Philip in 2021, and at other times of national mourning such as following the 