LONDON, UNITED KINGDOM - JUNE 17:  The Queen Mother (L) with Princess Margaret, the younger sister of Britain's Queen Elizabeth II, sit in an open top horse drawn carriage as they leave Buckingham Palace, central London for the short ride to Horse Guards parade, where senior members of the Royal family gather for the annual Trooping the colour ceremony, 17 June 2000. The Queen will take the salute at the historic military parade on London's Horse Guards, marking the sovereign's official birthday.  (Photo credit should read SUNDAY MIRROR/AFP via Getty Images)