Long-lived monarchs need long memories, so they can remember what needs to be forgotten. John Aubrey recounts the disastrous gaffe by the 17th Earl of Oxford – famous as one of the people who didn't write Shakespeare's plays – while ‘making obeisance’ at court to Elizabeth I. After it, Aubrey says, the disgraced earl escaped by going on his travels, to return to the royal presence seven years later. ‘My Lord,’ Elizabeth greeted him, ‘I had forgott the Fart.’

The second Queen Elizabeth has forgotten her youthful Nazi salute, along with the other fascism-lite imbroglios in which the Firm has snarled itself over the years. Likewise the queenly garlands lobbed to Nicolae Ceaușescu, late dictator of Romania – the then foreign secretary, now Lord Owen, thought it would be nice to have a pal in the Soviet bloc’s southern underbelly, and the genocidal kleptocrat’s liberal cred was duly talked up. Before the visit, the French president, Giscard d'Estaing, rang the queen to warn her that during their visit to Paris the Ceaușescus had ripped out all the gewgaws they could grab. The queen dispatched snatch-squads of footmen round the palace to nail down the silverware. It didn't stop Ceaușescu becoming a Knight Grand Cross of the Order of the Bath, a gong hurriedly clawed back twenty-four hours before he was shot. Denmark’s Queen Margrethe got in a day earlier, revoking the Order of the Elephant doled out to the dictator in 1980; that one’s been struck from the Danish rolls. Some things even elephants would rather forget.

In Walter Bagehot's phrase, monarchy demands a ban on 'letting daylight' – that is, the truth – 'in upon the magic'. You don't want to picture the queen on the can. Marion Crawford, her governess, was ostracised for life after spilling the (entirely anodyne) beans in The Little Princesses. 'She has gone off her head,’ the Queen Mother spat after vetting the book, which touched on her Bowes-Lyon clan's less than pulsating intellectual life. A court flunkey, Thomas Harvey, offered that it had spawned 'three not negligible poetesses', though one 'had disgraced herself by marrying a Papist, so we don't mention her at Court'. The book had made Princess Elizabeth 'deeply shocked & hurt & furious'. In a vain move to appease her mother, the publishers axed the story of the princess's scratching out from a school textbook the name of the inventor of chloroform – a man called Simpson. As censors know, the fact of censorship itself needs censoring.

Despite these traumas the queen has batted through to ninety. As with Diana's death, and the traipsing pageant of sprogs, weddings and jubilees, the birthday’s another of those moments when the country morphs into a twee version of North Korea. The Beeb goes into auto-drool; ITV is even worse. Mugshots of the supreme leader stare glassily out as bands blare and brass hats prink. She's taking on the holographic aura of her mother, whose last decades plied the pale between chiffon and outright inexistence. One of the better portraits of the queen, Chris Levine's Equanimity, actually is a hologram. Better still is the daub done for her 80th birthday by the child-molester Rolf Harris, as part of a 'BBC tribute'; the Beeb says the current whereabouts of this chef d'oeuvre are unknown. One of Harris's victims tipped off the queen as it was being painted.

Despite her years, the sovereign, known to Private Eye as Brenda, doesn't seem to be planning her own Brexit. Far younger monarchs in Belgium, the Netherlands and Spain have quit on grounds of age; even old Ratzo of the Holy See has shuffled off his subcinctorium. Meanwhile, the queen adheres to the throne as stubbornly as a seagull-splat baked to a sunshine roof. Commentators trot out the palace line that she sticks at it from a pitiless sense of duty. But everyone knows she knows that every extra day her reign grinds on is one less for that of Charles III. No one, maybe not even the dauphin himself, is clamouring to see the crown teeter atop those jug ears. Perhaps a corgi could be made regent till death or dementia claims him. The official plan, if the queen becomes permanently incapacitated, is that a quinquevirate including the Commons speaker John Bercow, Lord Chancellor Michael Gove, and Prince Philip – assuming he’s still available – will appoint a regent, presumably Charles. Or maybe they'll go for the corgi after all. Vivat regina!

Read more in the London Review of Books

Glen Newey: Bum Decade for the Royals · 23 January 2003

John Sutherland: Royalties · 14 June 1990

Linda Colley: Send them to Eton! · 19 August 1993

Caroline Murphy: Squidging about · 22 January 2004