Birds do it, bees do it, even continental dukes do it.

MONEY may make the world go around, but sex is the axis around which it spins.

MONEY may make the world go around, but sex is the axis around which it spins.

The knowledge that we all do it (or at least are a product of its enactment) is one of the bridges that carries us from childhood to adolescence. I can still remember my own horror on discovering - via a Family Doctor-style booklet - that my own parents must have done it, at least once. Not long after this unwanted revelation, Princess Margaret married Anthony Armstrong-Jones. The night of the wedding I barely slept, my teenage head a maelstrom of unrecognised erotic stirrings cut with disgust at the realisation that they were probably doing it at that very moment.

The yellow press understands this prurient pull only too well. Bishops, priests, politicians, judges and princes, the more rarefied the ether our social superiors breath, the more sensational (because unbelievable) their sexual fall from grace.

It's easy to forget, now that all's been proved true, the unnerving nature of the Squidgy-tape gushings of Diana and James Gilbey. It might sound like her, we temporised, but it couldn't be. It had to be fake. Then came Charles's witterings. Reaction ditto. The man might be a bit eccentric, talking to plants and the rest, but that the heir to the British throne even knew of the existence of Tampax, let alone could talk about it in such a manner was beyond fantasy. It too had to be fake.

One of the more lovable characteristics of the British character is an unwillingness to believe anything but the best of their "betters", even when common sense and hard fact combine to rub their noses in the truth. Heirs to the throne have always married for dynastic reasons, not for love. As a result, princes of Wales always had mistresses. It was, if you like, the perk of the position. But previous princesses of Wales, more often than not daughters of kings themselves, knew their place, knew when to turn a blind eye.

Diana, for all her father's acres, was a commoner. She didn't and wouldn't.

It was the knowledge that Andrew Morton's Diana - Her True Story was written with the tacit authority of the princess herself that led to its publication. But more than blowing the whistle on a sham marriage, Morton blew the whistle on the ruling class's, self regulating censorship that had rendered editors and publishers impotent for generations.

And if proof were needed, the first serious work of royal biography (and very good it is, too) since Morton moved the goal-posts was published last week, with revelations that set the establishment's teeth on edge. Author Sarah Bradford (vilified as a class traitor - although her title Viscountess Bangor is one, she owes to marriage) admits that Elizabeth - A Biography of the Queen is "racier" than she intended at the outset, which is hardly surprising since she began it in 1990, two years before Morton's bombshell.

But never again would the British public (and by extension the British publisher) be fobbed off with anything less than the truth, the whole truth and nothing but the truth. No one would have automatic immunity. And that included Philip.

The dashing young naval officer who had distinguished himself in the British navy in the war was known to his fellow officers as Prince Philip of Greece. His parents Prince and Princess Andrew had lost their throne in 1922 in a socialist coup. He was as charming a prince as Elizabeth's future subjects could wish for. That Princess Elizabeth was in love was self-evident.

Philip's emotions were never so transparent. But it shouldn't be forgotten that to all intents and purposes it was an arranged marriage, brokered by the intensely ambitious Viceroy of India, and Philip's uncle, Lord Louis Mountbatten.

Elizabeth might have been in love but her knowledge of history, particularly her own family history, would have prepared her for the reality of a royal husband's roving eye. Duty was all. What Elizabeth expected was loyalty, not fidelity. Unlike her sister Margaret, she was shy. Dances and parties held no attraction for her. Not so Philip. Until the announcement of the engagement he led a schizophrenic existence. During the week he was an impoverished naval officer at a training establishment near Bath 100 miles west of London. As ever in aristocratic circles there were girls you had fun with and girls you married.

PHILIP was independent in a way, not usual for a man of his class. Since the age of 10 he had been to all intents and purposes home-and family-less, spending school holidays from Gordonstoun at the house of whatever relative happened to invite him. The old guard of courtiers were uneasy with his lack of deference to them. "They felt he was rough, ill-mannered, uneducated and would probably not be faithful, "says Bradford. He certainly wasn't romantic, if the memory of his proposal, given to his official biographer, is anything to go by. I suppose one thing led to another. It was sort of fixed up." Because whatever the old guard might have thought, Philip was pretty much the only applicant for the post, no Catholics being allowed. Most importantly, he was royal, which meant he understood all the constraints and responsibilities being consort to a monarch would entail.

It was naive in the extreme to have expected this young leopard to change his spots just because the bars of his marital cage were gilded. But the British public, spoon-fed a diet of romantic love to counter the grim reality of post-war austerity, expected just that. The palace saw they got it. Privately Philip continued to enjoy the raffish side of 1950s cocktail bar society. He was a member of the Thursday Club, a jolly establishment that brought together journalists, actors, writers, humorists and politicians. Members included David Niven, Peter Ustinov, Patrick Campbell, Larry Adler - but also Stephen Ward (the notorious pimp figure in the Profumo case) and Cambridge spy Kim Philby.

When Elizabeth was pregnant with Charles, gossip columnists began to link Philip's name with the actress (who they inevitably described as a showgirl) Pat Kirkwood. That did it. The palace pulled up the draw-bridge and Philip's weekly trips down memory lane were stopped. But the crucial connections had been made; friends who didn't give a toss for convention and social preferment and who were themselves adept at keeping the public's prurient eyes at bay.

From Charles II, via the Prince Regent, William IV and Edward VII, actresses - whose reputation for less conventional attitudes to affairs of the heart made them suitable partners for romantic entanglements - had long been royal favourites. In theatrical circles during the 1960s Philip's liaison with one particular highly respected actress was common gossip.

In Europe, of course, all such stories have been given full rein. Philip was, they claimed, the natural father of his godson Max Boisot, the son of an old family friend, Helene Courdet, who in the 1950s ran a London nightclub. When the allegations surfaced again in the Bradford biography, the still glamorous Ms Courdet was quick to refute any such claims. That Philip paid for his godson's schooling at Gordonstoun, she told the Daily Mail this week, was just the repayment of a debt of honour, her own family having helped his in exile.

Courdet and Kirkwood are the only two "names" in the Bradford book and from the furore their publication caused you would think both had been caught in flagrante delicto. For annotated and footnoted chapter and verse of Philip's extra marital dalliances we shall have to wait for Kitty Kelly's much heralded expose. In the meantime Ms Bradford has at least opened the door to conjecture.

The "scurrilous accounts" that have circulated in the European press, she tells us, involve women who are "always younger than he, usually beautiful and highly aristocratic. They include a princess, a duchess, two countesses, and other titled and untitled ladies, some of them in the society horsy set." She gives no names.

However with the revelation this week of Philip's intercepted telephone call to a "plummy voiced" confidante, and the tabloids have been awash with profiles of "Philip's other women". Front runners included Lady Tollemache (Za), the Duchess of Abercorn (Sasha), the Countess of Westmoreland (Jane), and Lady Cavendish of Furness (Grania). But the odds-on favourite would appear to be Henrietta Dunne, married to Sir Thomas Dunne, Lord Lieutenant for Hereford and Worcester, described by the Tatler as "very pretty, very slim yet buxom, extremely glamorous, has wonderful skin and looks about 15 years younger than she is."

However, on this occasion at least, the truth is more prosaic than fiction. His "confidante" has been revealed as longstanding family friend Lady (Penelope) Romsey, who the prince has recently been teaching the sport of carriage-driving.

In Ms Bradford's view, the Windsors marriage is a spectacularly successful one. Unlike many couples who have been married for half a century, she tells us, Philip still shares his wife's bed. And frankly, now that the royal myth has started to unravel, that's where he'd better stay. Because, like it or not it's clear that the pre-divorce era of private infidelity and public composure is finally over.