The normal ebb and flow of British life gives way in the next four days to a series of street parties, flotillas, outdoor concerts and finally the appearance of an elderly great-grandmother on her balcony to wave to her subjects.

The pageantry is very grand and very British. But at the heart of the Diamond Jubilee celebration is a nearly universal sense of appreciation for the reign of Queen Elizabeth II, who is marking 60 years on the throne.

The queen was a vibrant young woman of 25 when she became the head of state of a faltering post-war nation. Today at 86 she remains strong of heart and stout of spirit, refusing to let age slow her pace or dim her smile, which if anything has grown more welcoming over the years.

Winston Churchill was prime minister when she became queen, and David Cameron, who wasn't even born then, is Britain's leader now. Elizabeth herself has no political role. But her royal mystique, the centuries of history she embodies and her own discreet charisma help define the very idea of Britain for the world..