Peter York: It's the old, old story of class

We are mesmerised by the furious email sent by Carolyn Bourne to her step-son’s future wife – it sums up a great national pastime

(Steven Haywood)

There's the Arab Spring and the Euro Summer Meltdown. Strikers are on our streets in an echo of Seventies Britain. But out there, in Dawlish, Devon, and Ledbury, Herefordshire, the great cavalcade of English life goes on. A stepmother thinks her daughter-in-law-to-be is uncouth and ill-mannered and suspects her family isn't up to much because they haven't put enough by to contribute to the wedding.

We all know about it and we're riveted: this is the stuff of class conflicts and generation gaps and all the micro-nuanced worries you get in the Diaries of Provincial Ladies and 19th-century novels. But, unusually, it has all been said Out Loud online in an email from Carolyn Bourne, the groom's stepmother, to the incoming Heidi Withers.

The email, full of fury of a kind understandable 30 years ago, has found itself halfway round the world via the curious Heidi. There is Australian comment, there are blogs, even a Today programme package. Some of the response completely gets what Mrs Bourne is on about – that people should buckle down and behave themselves in other people's houses, especially future parents-in-law's; that basic codes of manners make timeless sense. Others say: "Snobby old cow, who does she think she is?" The "real" mother-in-law (ie, young Freddie Bourne's mother, rather than step-mother), has joined Heidi's supporters from her home in Putney – where else? – although you wonder if she isn't seeking to settle a quite different score.

The way that Mrs Bourne uses the language of class – she says Miss Withers could do with a finishing school – but at the same time overdoes it in a Hyacinth Bucket way suggests she could be faintly delusional about her own standing. Both families sound like variants on the enterprising middle-class Middletons. One pair grows flowers, the other ran an nursing agency.

When people such as this do well, their houses are shown in wonderful magazines with titles such as 25 Beautiful Homes. But Mrs Bourne clearly feels herself closer to the Sloane heartbeat, with her flower-growing and horse-owning (anything equine sends Brits into flurries of class posturing).

Everyone concerned has been very rude indeed. Heidi's manners do sound a bit careless in the telling – in the way that lots of modern All-Bar-One-ish London working girls with interesting diets can be – and Mrs Bourne has gone way over the top, whatever the provocation. Heidi was doubly idiotic to release it to a waiting world, rather than mending fences, and her furious father, Alan Withers, will probably regret what he said about Mrs Bourne when he weighed in, not least because it'll confirm Mrs Bourne in her view that the Withers are NQOCD.

It is about class, of course, not in an inexorable Marxist sense, but in the old-fashioned British way of class-in-the-head, of reference groups, of styles and stances.

All this survives in places such as Dawlish and Ledbury – and beyond. It surfaced at every level in coverage of the middle-class Middletons by a London commentariat who'd normally say they were above and beyond all that archaic nonsense. But it remains one of the great diversions of English life. It's nothing like as important as it was, obviously, because the social order isn't what it was (but you don't have to be Mapp and Lucia to get the universal human drama in all this; it'll play in Papua New Guinea).

But is this stuff still defining for Brits – and limiting too? Research about the "British brand" confirms that we are seen this way. As class-bound and backward-looking, aloof and over-mannered. Much more Carolyn than Heidi, you might say. It all sounds incredible to anyone who knows how angry and uncouth most of Modern Britain is. And ironic to anyone who has read Eric Hobsbawm's The Invention of Tradition and who knows how traditions such as the Social Season were 19th-century inventions for urban plutocrats who wanted a bit of Old Posh.

There's a little bit of Carolyn Bourne in all of us. A friend recently brought his friend, an immensely rich young Middle Easterner, to my house. This young man – Ferrari parked outside, looked a bit like Saddam's boy, Uday Hussein, in the photographs – asked if I hadn't thought of knocking the hall of my 1813 Regency terrace house into the dining room. I explained that we had regulations about these things. He looked blank. I had to suppress the urge to ask him to leave immediately.

But do these entertainments connect in some real way to our substantive inequality and underachievement? If we didn't have the residual toffs-and-chavs panto in our national life could we be duller but fairer and better educated? Might we have invented Google, or still be the exporting workshop of the world like Germany 2011 if we'd been freed up from all that? Would Mrs Bourne's stepson Freddie, Heidi's potential husband, have been living somewhere other than Parsons Green and be running an online bike shop?

One of the great ironies of this story, with its references to the Old Order that Mrs B so obviously admires, good form, smart schools and castles (Mrs Bourne thought the young couple's plan to get married in one was vulgar because it wasn't their own) is what's happened to that world. Far away from Dawlish and Ledbury, the Season – what's left of it – the houses, the major public schools, the Big Art and the rest have been completely commandeered by the Global Rich.

In a clever piece in The Spectator, Harry Mount pointed out how the big Season's events – especially anything horsey – were now block-bought by American and Eurotrash hedgies, Chinese entrepreneurs, Middle Eastern flight capital and Bombay Billionaires. Everyone but Mrs Bourne. And the same goes for the toffs' old houses in London – 60 per cent of "prime" (£5m to £10m) and "super-prime" (£10m+) London houses and flats go to non-doms.

In the great London World-City State – increasingly cut off from the rest of the country – the old stuff is preserved and polished and parlayed into a new kind of Luxury Experience for people who don't have much of that back home. These people are immensely richer than British toffs, whom they see as a collection of useful upper servants – estate agents, concierges, butlers – looking after things when they're in New York or Abu Dhabi. They like the decorative panto, the Royal Family, the trophy antiques, and all the luxury stuff. But as for Mrs Bourne's traditional concerns about speech and behaviour – Good Form, Understatement, Breakfast – they're about as relevant to The Masters as Pygmy mating rituals.