The King's Troop Royal Horse Artillery fires a 41-round Royal Salute in Green Park in central London on Monday, June 10, 2013, to mark Prince Philip's 92nd birthday. (AP Photo/Anthony Devlin, Press Association)

Photo by: Anthony Devlin

The King's Troop Royal Horse Artillery fires a 41-round Royal Salute in Green Park in central London on Monday, June 10, 2013, to mark Prince Philip's 92nd birthday. (AP Photo/Anthony Devlin, Press Association)