Suddenly, brutally, inexplicably, a great star in the human firmament was extinguished and the world seemed a darker place. Diana, "queen of people's hearts", was dead. And in Britain, as in Ireland and around the globe, we wept.
Late that last Saturday night in August the dinner party chat predictably turned to the continuing travails of the House of Windsor. Diana had barely been out of the news. We never knew quite what to believe, or what she wanted us to believe. But the pictures appeared to tell their own story. Diana, it seemed, had found love with Dodi Fayed - son of Mohammed, controversial owner of Harrod's, and right royal thorn in the flesh of the British establishment.
In former years the princess had cut a lonely figure during the summer months while her sons holidayed with their father and the rest of the royals at Balmoral. This year she delighted the tabloids with a succession of holidays with Dodi, luxuriating in his millionaire's lifestyle, her pose and demeanour suggesting that the new life she desperately sought might finally beckon.
But would it last? More to the point, for some around the table that night, would it be allowed to?
The bitter divorce battles of the Waleses had left British opinion deeply divided about the monarchy, and about Prince Charles's suitability to succeed to the throne. Diana's sensational Panorama interview (which, over the healing passage of time, she may have come to regret) had fuelled the belief that "the establishment" had indeed been `'out to get her". Would that same establishment now permit her, should she wish, to marry Dodi - thus bringing his controversial father to its very heart, and, moreover, as step-grandfather to the future king? Or would they cheer her on her way - calculating that subliminal racist instinct would deem such a match unpopular and ease the way for Charles's own developing relationship with Camilla Parker Bowles?
Just hours later such intrigues and calculations seemed irrelevant and distasteful. Diana's body lay in a Paris morgue. The young princes, William and Harry, had been told of their mother's grotesque and untimely death, and of Dodi's, following that fatal, final paparazzi car chase. Prince Charles was preparing for the longest, loneliest journey of his life - to return with the body of the beautiful young woman who would once have been his queen, and who would never now find royal fulfilment as king mother.
Normal television and radio programming was suspended. And if the broadcasters had doubts about that judgment it was amply confirmed when the Prime Minister, Tony Blair - his voice cracking with emotion - appeared before the cameras to pay tribute to "a wonderful and warm human being" whose life was often touched by tragedy, yet who touched the lives of so many "with joy and comfort".
Mr Blair wondered how many times we would remember her, and in what different ways: "With the sick, the dying, with children, with the needy. With just a look or a gesture that spoke so much more than words, she would reveal the depth of her compassion and her humanity. We know how difficult things were for her from time to time. We can only guess that. But people everywhere kept faith with Princess Diana. They liked her, they loved her, they regarded her as one of the people. She was the people's princess and that is how she will stay, how she will remain in our hearts and our memories for ever."
Mr Blair undoubtedly captured the public mood. But the great populist could not have guessed the role he would be required to perform to guide the House of Windsor through a popular uprising which would shake it to its foundations.
An American stress expert quickly identified cause and effect: "Diana wasn't just a national icon, the beautiful princess. We identified with her as somebody who was in so many ways like us. Not only was she compassionate but she was a person who needed love and was vulnerable, and that's all of us."
Prof Gary Cooper suggested an impact even greater than the death of President Kennedy, and forecast feelings of anger, loss and guilt which would subsequently hit the British people like "an emotional atomic bomb".
The bomb exploded over the royals as they remained locked away in their Balmoral redoubt. From the moment the crusty courtiers pronounced on the arrangements for the funeral it became clear how out-of-touch they were.
It quickly emerged that this would not be a "royal" funeral because, of course, Diana had been stripped of her "HRH" as part of the price for her divorce settlement. Protocol decreed that the Union flag would not be flown at half-mast over Buckingham Palace, or the Royal Standard at half-mast over Balmoral. As millions queued, some for an astonishing 12 hours through the night, to pay their respects, anger grew that so few books of condolence were available for signing.
But as the carpet of floral tributes spread outside Diana's Kensington Palace home, it was the silent, empty Buckingham Palace which most inflamed public opinion. The hostility became positively threatening when it was announced that Queen Elizabeth planned to travel by overnight train from Balmoral, proceeding straight to Westminster Abbey, and return to Scotland immediately afterwards.
"Where is our Queen?" and "Speak to us Ma'am" screamed the tabloid headlines, as the public demanded assurance that the royals in fact shared their feelings of grief and loss.
Under discreet pressure from Downing Street, and Prince Charles, each and every royal plan was reversed. Relief was palpable among the crowds as the queen inspected the floral tributes outside the palace that Friday afternoon. The surge of feeling for Princes William and Harry, and for their father, brought fresh heartfelt tears. And there was the beginning of some regret, after Queen Elizabeth broadcast live to the nation, opening her heart "as your queen and as a grandmother". As she was later to observe, the royals can find public opinion difficult to read - not least because they are surrounded by deference, and because it is often conflicting. In that week they again discovered it can also be incredibly cruel.
By explaining the decision to stay at Balmoral, to comfort the young princes and give them space to come to terms with their loss; speaking of her own sense of loss, incomprehension and anger; and, most especially, by the warmth of her tribute to Diana and her declaration that there were lessons to be learned from her life and the extraordinary reaction to her death, Queen Elizabeth did much to heal the dangerous rift which had opened between her and her people.
Yet for a brief period thereafter it seemed not enough. At Westminster Abbey the next day the queen had to endure a public rebuke from Diana's brother, Earl Spencer, unprecedented in her reign.
In the lethal style of that Panorama interview, Earl Spencer paid tribute to a sister who had proved "she needed no royal title to continue to generate her particular brand of magic". The applause from the crowds in Hyde Park swept through the streets of London, bursting finally upon the Abbey itself. And with that message pounding in her ears, the queen heard Earl Spencer promise Diana that her "blood family" would do all it could to steer the young princes in their mother's imaginative and loving way "so that their souls are not simply immersed by duty and tradition but can sing openly as you planned". In that single phrase Earl Spencer encapsulated Diana's own accumulated indictment of the royal family.
The press seized upon the tantalising prospect of an appeal to the court of public opinion should the royals seek to bury the humane dimensions of Diana's legacy. There was excitable chatter about a battle between the House of Windsor and the truly "English" House of Spencer. But it was only ever that.
For the public anger of that week betokened an instinct still to see Queen Elizabeth and Buckingham Palace as the focal point for national sentiment and unity. There was ready understanding that further attacks on Prince Charles could only subvert the declared resolve to protect her sons. And there was the simple reality that, whatever their animosities, the Windsors and the Spencers shared a common and enduring commitment - to the royal succession. In death, in truth, Diana had joined them still more firmly together.