One of the oldest daily ceremonies in the West is the Ceremony of the Keys where the Tower of London is locked down for the evening ... a ceremony held every evening for roughly the past six centuries (minus the one night the Tower was attacked during WWII). Jack and his wife Caroline are invited by the guard to attend this ceremony after Jack saves the life of the Prince and Princess of Wales during an IRA attack in which 1987 novel (the invitation and ceremony were not part of the 1992 film adaptation).
Patriot Games