It is the little social conceits which cut pomp and circumstance down to size.

Eighty eight years ago when Elizabeth Bowes-Lyon married Bertie, the then Duke of York, the BBC respectfully suggested it record the Westminster Abbey ceremony for radio transmission. But the request was refused because the Archbishop of Canterbury was concerned that men in public houses would listen to the occasion with their hats on. He probably needn’t have worried. Deference was lodged in the nation’s bloodstream in the 1920s; even men in pubs would have sensed instinctively when to doff their caps.

But the snobbery contained in that vignette illustrates how Britain has changed since that royal wedding in April, 1923. Yet it wasn’t until 1997 that deference was finally sent packing with that seismic outpouring of public grief at the funeral of Diana, Princess of Wales.

Today the fire has gone from such hostility, leaving behind little more than indifference towards the crown. Even self-proclaimed republicans appear to have lost their radicalism. In YouGov’s survey for the current edition of Prospect magazine, just 13% want the monarchy abolished. That’s down a third on the 19% of five years ago.

Two movies have helped to restore royalty to relative public favour. Helen Mirren’s insightful performance in The Queen, and Colin Firth’s portrayal of a valiant George V1 in The King’s Speech have, by their own theatricality, strangely humanised a theatrical institution. Now next week’s wedding of Diana’s elder son to a princess-in-waiting, provides the royal family with another chance to consolidate what purpose it has left. Is it too fanciful to see this marriage as the middle-classing of the monarchy? Catherine Middleton is not only a commoner but the daughter of self-made millionaires.

Before Carole and Michael Middleton established their mail order partyware business in 1987, they were employed as British Airways cabin crew – hence the waspish soubriquet for the bride’s mother, Mrs Doors-to-Manual.

Sharper criticism has come with claims that the Middletons have cashed in on the wedding by merchandising such festive paraphernalia as royal bunting, corgi cake toppers and plastic hats emblazoned with the Union flag.

But isn’t that what the middle class is urged to do: seize an entrepreneurial opportunity especially when there’s a six-figure bill to pay towards the cost of a daughter’s big moment? And indeed if anyone knows the value of kitsch memorabilia, it’s the royals.

Hugo Vickers, royal biographer, is among the Middletons defenders: “People have said rude things about her ( Kate’s ) family, but they have behaved with poise and dignity.”

That’s certainly true of the bride herself who has already proved her wraithesome weight in tiaras by the discretion and grace she has brought to a far-from-fairytale role.

Of course, every family has at least one embarrassing relative whose presence threatens to mar its glorious occasion. Kate has Uncle Gary Goldsmith, a tattooed property developer and owner of La Maison de Bang Bang in Ibiza.

William has Uncle Andrew, the Duke of York recently deluged with damaging claims about friendship with a convicted billionaire paedophile, his contact with a Libyan arms smuggler, and his relish of gaudy party people.

But just when it seemed the wedding might be hijacked by news of Andrew’s risky networking on behalf of British trade, the Queen appointed her favourite son to an order of chivalry. By making the prince a Knight Grand Cross, the sovereign has effectively given two regal fingers to his critics.

In Europe royalty has also broken out of stuffy dynasties to enjoy a middle class embrace. Last June Crown Princess Victoria of Sweden, married her former fitness trainer Daniel Westling. In 2004 Crown Prince Frederik of Denmark, married Australian Microsoft executive Mary Donaldson. In 2002 the heir to the Dutch throne, Prince Willem-Alexander married an Argentine-born investment banker, Maxima Zorreguieta. This year Prince Albert of Monaco, now 52, will marry Charlene Wittstock, a South African-born swimmer.

On July 30, Zara Phillips, Princess Anne’s daughter, the Queen’s oldest granddaughter and “an all round good egg,” will marry England rugby star Mike Tindall at Canongate Kirk in Edinburgh.

From the 1970s, when the British monarchy attempted to brighten its glum grandeur by “letting in the daylight”, the Queen’s own children married outside royal circles. Such betrothals, it was argued, would bring the Windsors closer to the people, and in an unhappy sense they did: three of those original marriages ended in divorce. Now the royals belonged to Britain’s soaring rate of marital collapse.

As for us, freed from deference we often seem unsure about what has replaced it. In many ways we appear to have ditched obeisance for easy cynicism and the coarsening self-centredness of an entitlement culture. Here we are, a kingdom awkwardly trying to revive the worth of old, community values now that austerity is biting hard yet still not entirely inoculated against the grabby, nouveau hedonism which helped to land us in our present fiscal mess.

For her part, Diana didn’t change Britain but, more than any other royal or public figure, she sensed the change already happening in the country, and placed herself in the vanguard of its curious journey from buttoned-up restraint to showy indiscretion. More than 600,000 people crowded London’s streets for her and Charles’s wedding, a figure likely to be equalled on Friday. The personal backdrop to these marriages is very different, but the national backdrop contains troubling similarities.

On the nuptial eve of July 29, 1981, unemployment was spiking skyward, and race riots saw Toxteth and Brixton in flames.

Today high unemployment is wrecking millions of lives throughout the country, and grievous spending cuts are turning 2011 into the Year of Social Rage. Even so, there is wider recognition than for decades that a sovereign is preferable to a Buggins-turn president, and that the crown is a more profitable aid to British tourism than the weather.

Estimates of the wedding’s economic stimulus are around £750 million which is why the show will go on, and why the nation will down tools on April 29, not in strike action but to celebrate a bride and bridegroom we think we know but have never met.

So, welcome to Ruritania? Maybe, but if a personable young couple do bring sounder relevance to the monarchy, the hitherto unmerry House of Windsor might yet outrun The Mousetrap.

In the meantime, as always, we’ll just muddle through.