Now that we are in the holiday season, it feels entirely apt that the whole world is captivated by the most Richard Curtis storyline of all time, gazumping even Love Actually. Stop me if you’ve heard this one before: a charming English posho wants to find love, but British girls just don’t come up to snuff. Then along comes a glamorous American actress: she teaches him to share his feelings, he teaches her the value of real things, like roast chicken dinners with one’s friends from Eton. Ignoring the stuffy naysayers, he declares that he loves her, the country cheers and end credits roll. I speak, of course, of Prince Harry and Meghan Markle. And while I don’t have proof that Harry proposed in the rain, if he did I’m betting that Meghan didn’t notice.

Ever since the latest royal engagement was announced, historians have been dusting off the Wallis Simpson and Edward VIII references, even though (a) Prince Harry is not the King and (b) he probably never will be. But Harry and Meghan have nothing to do with British history – they are a British romcom from the late 90s/early 00s. Back then, almost every movie made in this country was predicated on the idea that posh British men can’t resist American women (and hats off to Guy Ritchie for going the extra mile with his real-life alliance with Madonna). Hugh Grant rejected Kristin Scott Thomas for Andie “call the acting coach” MacDowell in Four Weddings and a Funeral, and then rejected Emily Mortimer for Julia Roberts in Notting Hill (Cressida Bonas is clearly the Mortimer character in the Prince Harry movie: perfect, but insufficiently American). Jeanne Tripplehorn made a career playing the role of the American temptress (most notably in Sliding Doors) while Samantha Mathis cracked through Richard E Grant’s stiff upper lip in Jack & Sarah. But it was Curtis who jumped the shark with this trope in Love Actually. We will return to this unseemliness shortly.

As an American woman, I’m fascinated by the popularity of this cliche – in Britain, anyway. Because while British movies seem to think American women find the posh English accent irresistible, American movies invariably associate it with absolute evil. Moreover, despite living in this country for most of my life, I never dated an Englishman who owned even a dishwasher, let alone several castles, so if there is a magnetic pull between me and the British upper classes it is one I have avoided. But yes, some British toffs have been lucky enough to marry an American. Last year, for example, someone called James Rothschild decided to do America a favour when he took one of the Hilton sisters off its hands (no, not that one. I don’t think people called Paris are allowed in Brexit Britain).

Tatler magazine has been extremely exercised of late about the idea of American women carting off their precious poshos. Trying to fathom why this keeps happening, one heiress suggested: “American girls will give blowjobs way earlier than British girls because they don’t consider it sex.” Well, there’s a marital tip I don’t remember hearing from Cinderella’s fairy godmother. Stick that in your next movie, Disney.

The idea that Americans are sluts lies at the heart of this cliche about American women and British toffs, from the rumours about Wallis Simpson’s sexual prowess to Richard Curtis movies. In Four Weddings, MacDowell wows Grant by revealing that she’s slept with more than 30 men. In Notting Hill, Roberts sleeps with Grant even though she’s in a relationship with Alec Baldwin. In Love Actually, this idea reaches its climax when January Jones and her friends eagerly shack up with Kris Marshall, such is their love of the English accent and insatiable American sluttiness. For me, the Special Relationship officially ended when Marshall tells Jones he’s from Basildon and she makes an orgasmic yelp.

As flattered as I am by the suggestion that my sexual skills are so great I could literally seduce a country, the truth is a lot less sticky-palmed: to a British toff, an American seems excitingly untraditional, while for an American, a British toff seems thrillingly traditional; the two meet, hopefully, in the middle, somewhere around the roast chicken dinners. Also, the American accent is reassuringly classless, so Harry’s family won’t be able to tell which school she went to from the way she pronounces “off”. Thus, the most class-obsessed people in the most class-obsessed country in the world, the English upper classes, can date a far broader range of women than the blond Sloanes allowed to them here. After all, it’s only in a Richard Curtis movie that a posh British man ends up with an English tea lady. In reality, they can slum it with the Americans.

• This article was corrected on 9 December 2017; Jeanne Tripplehorn was not in Bridget Jones’s Diary as previously stated. It was further amended on 13 May 2022; in Four Weddings and a Funeral, Andie MacDowell’s character reveals that she’s slept with more than 30 men, not more than 50 as an earlier version said.