The patriotic bunting is ready, the golden carriage on standby, the boats freshly painted, the shops filled with royal souvenirs.
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.
Britain is marking Queen Elizabeth II's 60 years on the throne with a four-day holiday weekend of ceremony, symbolism and street parties.
The queen will celebrate Saturday at the Epsom Derby, a highlight of the horseracing calendar, and on Sunday she will lead a 1,000-boat flotilla on the River Thames. Monday's festivities include a pop concert in front of Buckingham Palace with Paul McCartney and Elton John, and festivities climax Tuesday with a religious service, a procession through the streets of London and the royal family's appearance on the palace balcony.
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 queen, who acceded to the throne in 1952 on the death of her father, King George VI.
Elizabeth was a vibrant young woman of 25 when she became the head of state of a faltering post-war nation. 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.
Alan Watson, a member of the House of Lords who has written a book about the queen, said the jubilee is a joyous occasion for many Britons who see the queen as a symbol of stability.
"These 60 years have been years of really dramatic change in the UK, the tectonic plates have moved," he said.
"The country has lost its empire and is no longer in the front rank of power, and I really think that change has been enormously eased by her and what she represents. My feeling is she has enabled change by her reassurance of essential continuity."
When Lord Watson joined the queen at a rain-soaked tree-planting ceremony in Richmond several weeks ago, he said he was struck by her buoyant mood as the Jubilee approached.
"I got the clear feeling that she is really enjoying things," he said. "It was pouring rain, but she really looked radiant, a happy person. I think she feels very content in herself. I think she is satisfied with how the reign has gone."
Elizabeth has weathered shaky times with her children, whose marriages have tended to break apart, and her popularity suffered after the 1997 death of Princess Diana, with some finding her response to the tragedy to be cold and out of touch with public sentiment.
The late princess was an international superstar. And the queen was seen by some as overseeing the royal push to cast her adrift after the breakup of her troubled union with Prince Charles, the heir to the throne.
But all evidence suggests the queen's connection to her subjects has recovered from those blows.
There was overwhelming support for Elizabeth at the last great celebration that focused on her role — the Golden Jubilee bash that in 2002 marked her 50 years on the throne.
The event is remembered not just for the concerts and the parties but for the spectacle of an estimated 1 million people gathered in front of Buckingham Palace.
Palace officials are hoping this simple show of affection will be repeated on Tuesday when the commemoration climaxes with another balcony appearance.
Not everyone in Britain will be celebrating. The anti-monarchist group Republic plans a riverbank protest as the flotilla goes by on Sunday — followed by a pub night where royal refuseniks can drown their sorrows.
But royal officials have reason to be optimistic. Newspaper polls this week suggested that affection and appreciation for Elizabeth cut across all ages, social classes and political affiliations.
For many, she is a living link to the challenges and triumphs of World War II, when she was a young princess who helped with the war effort, even learning how to drive and service heavy vehicles with the Auxiliary Transport Service.
Her staying power is impressive. Elizabeth is the oldest person to reign over Britain, and only Queen Victoria, who took the throne at an earlier age, had a longer reign.
It is of course true that some are indifferent or hostile to the monarchy, with its vast inherited wealth and status, but few question the dedication or sincerity of the queen.
"She's done a very good job," said Jean Robson, a London retiree. "She works so very hard. The family's had problems like every family, and she's dealt with them very well."
Robson said she and her family admire the royal family and its longtime role in the nation's life.
"We're very lucky to have them," she said.
The queen, and the royal family, have benefited in the last few years by the newfound maturity of Prince William, who married the former Kate Middleton in a spectacular ceremony last year, and Prince Harry, who has put his partying days largely in the past as he focuses on a military career.
The young princes have stepped up their official duties, at times representing the queen abroad. Their natural flair has given what had been an aging monarchy a badly needed touch of cool.
This effect has been accentuated by Kate, who has brought poise and fashion flair to her new position as the Duchess of Cambridge.
She has won raves for her ability to bring new pizazz to the royals, and her presence at the Jubilee festivities is expected to produce pictures and TV images that will be seen throughout the world.
Associated Press writer Sylvia Hui contributed to this report