HAVE YOU NOTICED what day it is? Yes, Friday. And the date? December 13. So that makes it Friday the . . . oh my God! It’s Friday the Thirteenth. Bolt the doors. Hoist the garlic. Don’t even think about leaving the house. And if by awful mischance you are already on an aircraft, or a Tube train in a dark deep tunnel, or on a No 13 bus approaching the 13th stop on its 13th journey of the day . . .well, I just hope Uranus is stable, that’s all. You’re going to need all the favourable astrological portents you can get.

But what am I writing? It’s all nonsense, isn’t it? I mean, more than usual. Any statistician will tell you that fewer accidents happen on Friday the Thirteenth, because people avoid doing “accident waiting to happen” things like walking under ladders, or asking a conman to help them buy a flat. And surely only the most unimaginative maniacs go on the rampage on Friday the Thirteenth, and then only in very bad films.

Yet millions of us cling to some vestige of Friday the Thirteenth fear, which we imagine to be as old as the hills. Most think it is something to do with there being 13 people at the Last Supper. But the Last Supper happened on a Thursday! What’s more, although the inestimable Oxford Dictionary of English Folklore traces a belief about Friday being unlucky to Chaucerian days, and “13 phobia” to the 17th century, its editors can find no superstitious conjunction of Friday and 13 earlier than 1913! In other words, it’s a 20th-century fraud. Quite possibly some Hollywood publicist was behind it from the start.

The same is true, it seems, of many other supposedly ancient superstitions that linger like shreds of old wallpaper in the pristine, rationalist rooms of the 21st-century mind. Like many people, I say “touch wood” when I mean “I hope”. I thought I was making some faint connection with the Celtic Druids who believed that trees contained benign spirits, or perhaps with the Catholic Good Friday rite of kissing “the wood of the Cross”. But the Oxford Dictionary is scathing. “There is no basis whatsoever for these explanations, beyond guesswork,” it says.

And the experts are equally disdainful about the antiquarian claims of Britain’s other “Top Ten Superstitions”. Only one, that spilling salt brings bad luck, is more than 400 years old. True, the widespread superstition about black cats dates from the 17th century (though there is still no agreement about whether the felines in question bring good luck or bad). But the rest — broken mirrors, magpies, dropped scissors, walking under ladders, umbrellas indoors, new shoes on a table, etc, etc — turn out to be nonsenses concocted in the 18th, 19th or 20th century. And most of the “lucky rituals” that saturate the world of sport, gaming and entertainment are no older than my patio doors.

This discovery has had a big impact on our understanding of antique cultures. Or rather, our misunderstanding of them. Until quite recently many anthropologists subscribed to “survivals theory”. This held that superstitions are the last remnants of a vast, pre-Christian cosmology which could thus be reconstructed by retrospective deduction. But now it appears that our favourite superstitions were largely invented by relatively modern man when his belief in “conventional” religion started to wane. So although most people don’t “pray to God” any more, many still believe in some sort of “fate” which can be influenced, albeit marginally, by simple measures like not sending a sick person a mixed bunch of red and white flowers (unless, of course, you want to finish them off).

Nor are such superstitions merely the opium of us gullible peasants. Some of the sharpest cultural minds have also been susceptible. Take Orson Welles. When he produced his all-black Macbeth in Harlem in 1935, he took the reputation of “the Scottish play” for triggering misfortune so seriously that he hired a witch doctor to sacrifice goats each night on stage — this being calculated to ward off angry spirits (except, presumably, the furious spirits of the dead goats).

Alas, the tactic worked only too well. When the vitriolic Herald-Trib critic Percy Hammond savaged the production, Welles agreed to allow the witch doctor to murmur a few “harmless” voodoo curses. Twenty-four hours later Hammond dropped dead of an unexplained illness.

Enjoy Friday the Thirteenth. I just hope you make it off that train safely.

THE QUEEN should award herself a gong for endurance when her latest annus horribilis grinds to an end. She has lost her mother and sister. She had to sit through Sir Paul McCartney leading a singsong in her back garden. The Burrell Affair revealed the Royal Household to be London’s campest meat-market. Her daughter has acquired a criminal record.

And now comes the publication of War of the Windsors, an extraordinary work of what one might call “speculative history”. Its four authors (one, Stephen Prior, said to be a former member of the world’s most productive literary agency — British Intelligence) allege that the Queen’s uncles, Edward VIII and Prince George, were incorrigibly promiscuous bisexuals; that Lord Mountbatten, besides plotting to overthrow the Wilson Government (an old charge) was involved in the Kincora Boys’ Home sex scandal; that the House of Windsor was tangled in a plan to make a truce with Hitler long after Britain had gone to war; and that the Soviet spy Anthony Blunt was George V’s bastard son, and hence the Queen’s uncle.

Is any of it remotely true? Well, how the hell do I know? I’m not a royal butler. One day, no doubt, someone will be allowed to write the real, unexpurgated history of the House of Windsor in all its tangled complexity and complicity. But since Shakespeare still felt it prudent to whitewash his own monarch’s shadier ancestors more than a century after they had died, I shan’t hold my breath.