Matthew Norman: Normality isn't what we expect from our monarchs

I can't imagine Kate Middleton having the captain of the England rugby team smuggled into Kensington Palace in the boot of a car

Without British Airways there would be no Kate Middleton, so it seems proper payback that the national carrier will be a leading beneficiary of her marriage to Prince William. Untold thousands will fly with BA to London from across the globe for the holy wedlock of Prince William and the lovely Kate some time next spring or summer. And many, many more will fly out of Britain to escape it.

Second guessing so diverse and complex a readership is an idiot's game, and being an idiot I believe I know how most of you are feeling about this. It might safely be boiled down to this tortured, four-word plea: make it go away.

But it won't. Barring some heartrending split between this depressingly inoffensive young couple, we're stuck with months of mawkish drivel from determined royalists and vinegary carping from committed republicans. For those of us stuck somewhere in the indifferent middle, it's going to be hell on earth.

So let us dredge up the old Blitz spirit, and do what those brave EastEnders did whenever William's late, great granny insisted on looking them in the face. Let's find one oasis of cheer in the desert of foolishness that stretches ahead further than the eye of the Comptroller of Nuptial Dates can thus far see.

The best I can manage concerns the most dramatic revival of something thought defunct since rickets. I refer to social mobility. Those who believed this fuddy-duddy notion had been canned in the dustbin of history will rejoice as they read voraciously about the future princess's antecedents. Her maternal grandfather was a builder in Middlesex, while her dad's dad was a pilot (not even, like William, in the RAF; a commercial pilot, if you please). As for her parents, Carole and Mike, who are now in trade (mail order, forsooth), they met in the mid-1970s as BA cabin crew colleagues.

Passing over the revelation that aviation history boasts a straight airline steward, the sadness concerns the timing. Mike had swapped performing safety demonstrations and pushing the duty-free trolley for a job on the ground several years before Kate's birth in 1982. So there appears no chance that she has the honorary life membership of the Mile High Club conferred by conception 36,000 ft above the Adriatic shortly before the captain announced: "Ladies and gentlemen, we will shortly begin our descent to Dubrovnik". Had she been, this would be an even more amazing rags-to-royalty story than a King of the Jews born in a stable.

Yet her social ascent is vertical enough. I can't think of a commoner marrying a monarch or anyone in direct line to the throne since the Catherines Parr and Howard were joined in matrimony to Henry VIII. Those who believe the rumour that the hyper-ambitious Carole cajoled Kate into going to St Andrews because that was William's choice of university will assume she christened her daughter Catherine with that 16th-century double precedent in mind. If so she is a woman of great foresight, and a worthy grandmother-in-waiting to a sovereign to be crowned, if William enjoys the span his genetic inheritance through the paternal line suggests, some 70 years hence.

Whether this marriage will make it more or less likely that the House of Windsor survives that long is hard to call. On the one hand, William's choice of bride is clearly a step along the cobbled path towards a bicycling monarchy. In fact, the Prince and his younger brother have already moved in that direction by reacting like normal people at sports events, albeit with despair rather than the ecstasy shown by Spanish royals whenever Rafa Nadal wins Wimbledon or the footballers a major trophy. The presence at his side of the spawn of a DC10 will speed the process of normalisation.

On the other, does anyone really want them to be normal? Isn't the sole justification for the anachronism of monarchy the hilarity it induces ... the sense of affectionate bemusement caused by a set of mores, typified by William's father ringing Camilla from the honeymoon yacht within days of marrying his mother, that everyone else other than Lord St John Stevas of Fawlsley and William "Backstairs Billy" Shawcross thought outmoded in 1957?

And these two do seem worryingly normal. Even from what infinitesimally little I know of Kate, I can't imagine her having the captain of the England rugby team smuggled into Kensington Palace in the boot of a car. Nor can you envisage William reinterpreting a tenet of Buddhism to express his desire to be reincarnated with Dr White stamped on his arse.

Ever since Prince Harry returned the swastika to the fancy dress hire shop, this family has wilfully abdicated its duty to repay the annual 14 odd shillings each of us gives it by amusing us with their nonsense. The Duchess of York tries, bless her, but her corkscrew spin to Eurotrash disgrace after a short-haul royalist flight made her an irrelevance long ago.

The British monarchy is a fearsomely tough old broad, much like the monarch herself, with a gift for responding to danger. The flame of republicanism that blazed for a few days after Diana's death before being extinguished by the Queen's beautifully judged live broadcast hasn't flickered since. The marriage of William and Kate, and the life of tedious middle class respectability they seem destined to share, will keep it safely snuffed.

Me, I'm perfectly content with that. Of course it is ridiculous to maintain a God-anointed monarchy in an atheistic age. But we are all ridiculous to ourselves, or should be, and externalising and celebrating the ridiculousness by sticking a crown on its head is one of the saner lunacies we know. So little binds us as a country any more. Take away 37 hours a week discussing The X Factor, and what is there but the royals?

The House of Windsor has, like the parents of its next important member, become grounded – and on balance, despite regretting the loss of its more diverting insanities, that's no bad thing. So join me in taking a moment from booking a foreign trip from April until September next year, to offer a warmish welcome to the forthcoming Princess of Wales. Cabin crew, doors to manual, but don't bother with the safety belts. It isn't going to be a bumpy ride.