In the early Eighties a new borderline was being crossed in the privacy debate. So long as royal "private" lives were irreproachable, it was possible to defend "privacy" in general from a high moral platform. It was more difficult once that changed.
A leader in the field of freer sexual morals was the Queen's second son, aged 21 at the time of the Waleses' wedding, and increasingly seen as the late 20th-century equivalent of a Regency buck. The popular press was full of Prince Andrew's exploits, about which he did not bother to be particularly reticent.
Unlike his older brother, whose female relationships had tended to be upper class, Andrew's liaisons were more democratic, adding to the tabloid frisson. He acquired an inevitable nickname. "Randy Andy's highly publicised friendship with actress Koo Stark and Katie Rabbett, and his alleged affair with former model Vickie Hodge deeply upset the Queen," Audrey Whiting, the Sunday Mirror's royalty watcher, confided in June 1984. "She has made it clear she will not tolerate any more `indiscreet behaviour'."
Actually, the opposite was the case. The Queen made little attempt to curb the activities of her children, especially the younger ones. "She should have told them off more," considers one ex-courtier. "The trouble is that the Queen hates dictating to the family," says another. "I think she's terrified of her children," says a former adviser to the Prince of Wales. "She's afraid they won't do what she tells them."
If she was not a hugging mother, she was also a far cry from a censorious one. She treated Andrew with a special indulgence. "She was happy about his relationship with Koo Stark - a very nice, gentle girl," says a former courtier.
Each month of the 40th anniversary year of the accession seemed to bring a new embarrassment, humiliation, error, or accusation. The year 1992 was an annus horribilis indeed: in January came the photographs of Fergie on holiday with a Texas oil millionaire; in February, the image of "Diana alone" at the Taj Mahal; in March, the separation of the Duke and Duchess of York; in April, the divorce of Princess Anne and Mark Phillips; in May, the departure of Fergie from the marital home, taking her daughters with her ...
But it was the problems of the Prince and Princess of Wales which caused most concern. In retrospect - in view of the episodes apart, semi-public quarrels and heart-to-hearts with garrulous friends - the remarkable thing is that the details remained secret for so long. To those who knew the couple well, the gap between the gauchely reflective Prince and the sharp, whimsical, brittle Princess was obvious within a year of their wedding. The Queen and Prince Philip chose not to notice. When Diana turned up late for meals, or left them early without explanation, her behaviour was ignored.
Charles, according to his friends, blamed his parents for not being more supportive. "He felt very let down by his unsympathetic mother and father," says a confidante. "When his marriage went wrong, he felt criticised by them."
Perhaps they were more concerned than they seemed. "The Queen was aware of stresses and strains," says a courtier from the period. "She was wholly sympathetic towards Charles, in fact rather one-eyed in her approach." Once, the Queen and her husband dined a quatre with friends whose children also had troublesome marriages, for the specific purpose of "wondering together where they went wrong".
The difficulties of the Prince and Princess had long been the subject of rumour - but little of it was backed by hard fact, and most only half- believed by non-tabloid readers. Then in June 1992 came Diana: Her True Story, a book by Andrew Morton clearly produced with the encouragement or connivance of the Princess. It was the logical outcome of the trend towards openness, ending a century and a half of royal reserve on personal matters and replacing it with the opposite: royal exhibitionism.
Readers were intrigued to be told - and the Royal Family was horrified for the world to be informed - that while pregnant with a potential future king, the Princess of Wales had thrown herself down the wooden staircase at Sandringham; that she had slashed her wrists with a razor blade; and that, in an attempt to rescue her from the terrible psychic consequences of becoming one of the most admired women in the world, she had been dispatched to a succession of therapists.
The book rang true, and it was a new kind of book: although its style was that of a romantic novel, it could not be dismissed as scandal-mongering. It was a moral classic about a young woman who had entered the legendary world which millions dreamt about, and who found that the "model family" was a myth.
There was another aspect to the book. If it presented the Princess as vulnerable and unable to cope, it also painted a hostile portrait of her husband - blaming him both for his lack of understanding and for his continuing relationship with Camilla Parker Bowles. At the same time, Morton presented the Royal Family not as a haven of domestic virtue but as unhelpful and self-absorbed.
The strongest theme of the book was a juxtaposition of warmth and coldness. On the one hand, there was Diana, "tactile, emotional, gently irreverent and spontaneous"; on the other, there were the icy Windsors, with their unfriendly mansions where the Princess found the atmosphere so dispiriting that it was liable to bring on a bulimia attack.
A couple of decades earlier, a seriously negative report about the Queen's family would have been unprintable. The Morton book released all inhibitions. Now a bounty hunt for worse revelations, grimmer details, wider scandals, began in earnest.
In August, the Daily Mirror published a picture of the Duchess of York - separated, but still married - bare-breasted beside a pool having her toes kissed. The simmering circulation war between the major tabloids became total: editors ransacked attics for old material which, in the past, had seemed too damaging to use. The Sun made public the two-and- a-half-year-old tape recording of a telephone conversation in which the Princess of Wales spoke with great affection to a friend, James Gilbey, who referred to her as "Squidgy"and "Squidge". In it, she described her marriage as "torture". Recounting one difficult family meal at Sandringham, she said: "I was very bad at lunch and I nearly started blubbing ... I just felt really sad and empty and thought `bloody hell, after all I've done for this fucking family'."
The monarchy's domestic problems became part of its evolving image: no longer a model family, but an all too common one - although, as it was also frequently pointed out, three failed marriages out of four children was above the national norm.
There were plenty of shocks and embarrassments to come. In the autumn of 1994 Jonathan Dimbleby's biography of Prince Charles contained an admission from Charles of his adultery with Mrs Parker Bowles and presented Diana as quixotic, self-obsessed and paranoid. But it also revealed the Prince's own view of his childhood and upbringing.
Morton had painted the Queen as an aloof mother; not unkind, but disengaged. Others had commented on the Queen's reported inability to show physical affection, and tendency to put her children after her duty. Dimbleby's references to the Queen and Prince Philip were brief. Since, however, they were assumed to come from the Prince of Wales, they helped to establish a new legend. The Queen was presented as cold, Philip as a bully. The monarch and her husband, formerly set in the nation's imagination as the ideal mother and father, became indifferent parents, who caused the marriages of their children to break down by starving them of love.
The main impact of the book was to stir, yet again, public interest in the Waleses' marriage, and to raise the question of whether the Prince was fit to succeed. The Coronation chant "May the Queen live forever" became the fervent invocation of some of the monarchy's strongest supporters. The world divided into two camps: those who sided with the Princess of Wales - who included many feminists and constitutional reformers - and supporters of the Prince.
Then Diana returned to the offensive. "There is a studied casualness in her relationship with the Royal Family," a friend of the Queen reflected. "She has a `What the hell, I'll show them' sort of attitude." In November 1995, stung by Dimbleby's suggestion that she was psychologically unstable and a "problem", she agreed to take part in an hour-long interview on BBC Panorama.
After the broadcast had been announced, but before it had taken place, a friend of the Queen and Duke who spent a weekend with them was struck by how little they seemed to be showing the strain. Nothing came up in conversation except the rural pursuits that always interested them, with plenty of jokes. While the whole world was arranging to be at home to watch Panorama, the subject of the day was not even hinted at.
Delighted with its prize, the BBC abandoned any pretence at objectivity, restricting the interview to the gentlest of questions and retaking shots indefatigably to produce a fluent package. "You will never be King," Diana had told Charles, according to one of his friends, "I shall destroy you." On television, she merely indicated that she did not expect her husband to succeed and offered her son as an alternative.
The Queen did not let her daughter-in-law have the last word. After the Panorama interview, she consulted the Prime Minister, the Archbishop of Canterbury and senior household staff. Then she made a pre-emptive strike, writing letters to both the Prince and Princess pronouncing, with her husband's support, that an early divorce was desirable. The tone of the letters was more measured than she felt. According to one close source, they came out of a deep exasperation, and of a desire to state her position in incontrovertible prose because, as she had learnt, "bulimics rewrite history in 24 hours".
When the contents of the letter became publicly known, the Princess of Wales at first seemed taken aback. Then her lawyers began negotiating a divorce settlement in earnest.
As for the Queen, she carried on. She led a more solitary existence than in the past. The number of intimate friends among her contemporaries was declining. In September 1993, Bobo MacDonald, her childhood nurse and then royal dresser for 67 years - and her relentless custodian, daily companion, confidante and friend - died at the age of 89. With her husband often away, the Queen frequently dined on her own.
If she was lonely, she did not say. But she was not immune to the strains and humiliations suffered by the Royal Family. She took comfort in her mailbag - many times larger than at the start of the reign - of letters written by ordinary people expressing concern. They often affected her more than the polite or embarrassed sympathy of friends. "You see," she would say, turning them over, "they really do understand."
Edited extracts from The Queen
By Ben Pimlott
Abridged by Paul Vallely
To be published by Harper Collins on 14 October, price pounds 20
Ben Pimlott 1996