The House of Windsor is set to party. And if Queen Elizabeth and her courtiers have anything to do with it, it promises to be a long one - stretching all the way to 2002.
The immediate focus - national and international - is on Prince William and this weekend's publication of official photographs to mark his 18th birthday on Wednesday. The future King of Britain is in the middle of his A-Levels and revision may prevent him attending that night's big bash at Windsor Castle. There the royals will privately celebrate the Queen Mother's 100th birthday (August 4th), as well as Princess Margaret's 70th (August 21st), the Princess Royal's (August 15th) and the Duke of York's 40th (already past, on February 19th).
Next month the nation will celebrate the Queen Mother's remarkable life. They will do so with enthusiasm; she is frequently described as Britain's favourite grandmother. And there will be a widespread hope that she survives in turn to celebrate her daughter's golden jubilee in two years' time.
That, for Queen Elizabeth, will be the big one. We already know that the sovereign is hoping Mr Blair calls his general election next year, so that party politicking doesn't get in the way of the planned celebration of her reign. After the trials and traumas of recent years - the divorces of three of her four children, the spectacular war of the Waleses, the revelations about dysfunctional family relationships, and the public revolt following the death of Diana, Princess of Wales - the golden jubilee will provide an important test of popular support for the monarchy and a crucial indication of its future security.
Remarkably, after all that has happened, that future still seems pretty secure. Barely three years ago, things seemed very different. Diana's tragic death came just months after New Labour had swept a discredited Tory party from power after 18 long years. Sun-dried tomatoes weren't the only new fashion. The talk then and for some time after was of Cool Britannia, New Britain, a "young country". The Blairite programme of constitutional reform was devolving power and would shortly abolish the hereditary peerage. In that context many, inevitably, pondered the relevance of a hereditary monarchy. And the outpouring of emotion which attended Diana's death itself suggested a significant change in the British psyche.
But fashions change, ever-more swiftly - a fact known to none better than Queen Elizabeth herself. As one commentator said recently, her strength and security have been found in her steadiness, her seriousness and her innate conservatism, not in "rushing to be relevant" or by trying to do too much. There is little talk now of Cool Britannia. After just three years in power, Mr Blair finds himself handbagged by members of the Women's Institute during a speech in which he attempted to link New Labour's modernity with devotion to traditional British values. And significantly - even at the very height of his powers, and of public disillusion with the House of Windsor - the Prime Minister worked hard to restore the bonds between the sovereign and her subjects.
It would be easy to exaggerate the extent to which New Labour helped the royals modernise their act - as it is to depict many aspects of royal life and protocol, still, as out-dated and sometimes plainly absurd. But the queen heard her people in those angry days after Diana's death, and responded to them. It was clear at the time that that was all that was required.
Earl Spencer may have excited a wave of republican speculation with his assurance that the "blood family" of Prince William and Prince Harry would play a decisive part in their future upbringing. However, the House of Spencer was never going to play any part in subverting or threatening Prince William's eventual inheritance as head of the House of Windsor.
Whatever angry words were uttered during the dark days of her estrangement and eventual divorce from Prince Charles, by the time of her death it was clear this emphatically would not have been Diana's wish. Nor the wish of those who mourned her.
On that unforgettable day when they buried Diana, Earl Spencer's words truly did find a resonance with the watching public. We gasped as he vowed to help steer the young princes in Diana's imaginative and loving way, "so that their souls are not simply immersed by duty and tradition, but can sing openly as you planned".
The Prime Minister said then that a more compassionate society should be Diana's true legacy, and the public agreed. They had learned of Diana's hurt, and they felt deeply the hurt and pain of her two boys. They were determined that William and Harry should never be or feel similarly hounded, and the press entered the pact. With a few minor exceptions, that pact to protect Prince William's privacy during his remaining school years has held remarkably well. But is it now to end just because he is entering his majority?
The Palace has always understood that Prince William's 18th birthday must be a public event - hence the photographs, and the unprecedented television footage of his life at Eton. William himself has thanked the press for allowing him that freedom. But in answer to questions, he has confirmed what has been plain thus far from his demeanour - that he does not like the attention: And why would he?
Commentators tell us that he appears to have survived relatively unscathed from the events of recent years. We can trust that it is so, but we do not, cannot know. What we do know is that while the law may now define him as a man, at 18 he is still close to boyhood. As Libby Purves observed acutely: "Eighteen still doubts itself, keeps its dreams private, wants to experiment with life, and longs to achieve something in its own right rather than through accident of birth. Eighteen is vulnerable, and can take a knock-back very hard."
Few could disagree that, for all his privilege and wealth, this man/boy/future king has had more than enough knocks already. The earnest hope will surely be that he will again be left alone to enjoy his gap year and, after that, his life at university. Certainly the wish for a "happy birthday" would ring hollow should the lessons learned three years ago prove so quickly forgotten. If the people want William one day to reign over them, they will instinctively know that he will do so the better, and more happily, if his soul is indeed allowed to sing openly as his mother planned.