I'm sure I can't be only person who thinks that Prince William has made a ghastly mistake in ending his four-year romance with Kate Middleton.

Just when you feel quite relieved that the heir to the heir to the throne has actually found someone evidently loyal, dependable, sensible and sane - along with being freshly attractive in the right kind of way - he goes and casts her aside, allegedly hinting that she's not as much "fun" as Chelsy Davy, the current squeeze of roistering Prince Harry.

According to tabloid reports on the ruptured romance, William also, apparently, thinks that Chelsy is "very bright" - although clearly not bright enough to realise that her Christian name is a horrendously chav-tastic spelling mistake.

Considering that from the neck up, buxom Chelsy looks like someone you might find serving behind the counter of the local shop in Royston Vasey, (only less classy) I can only think that Prince William is having some kind of early-life crisis - a thought borne out by those reports of his behaviour during a recent boozy night out in a Bournemouth nightclub.

Kate, meanwhile, always looked quite perkily pretty to me, even in those frumpy tweed outfits she wore to the Cheltenham races. In fact, I often thought she looked rather like early photographs and portraits of the young Elizabeth Bowes-Lyon, the late Queen Mother, which, by my reckoning was the last time the royal family bloodline benefited from an injection of good, down to earth, sensible genes.

As for intelligence, Kate did actually manage to get a decent degree from St Andrew's - one of the country's top universities. In fact, I think you might find that her upper second in history of art was a grade or so higher than William's efforts in the faculty of geography.

It certainly must have enabled her to have some politely informed conversations with William's rather wonderful granny while touring the royal collection on family visits. Let's face it; you can't imagine Chelsy swapping notes with the Queen on the merits of a Caravaggio, unless it was the name of the latest special on the cocktail menu at Boujis.

Some of the most unsettling stories circulating regarding the end the Will and Kate show focus on the fact that Miss Middleton's background might not have been grand enough for some of William's chums. The fact that her mother, Carole, was merely an air hostess who could trace her family back through generations of Durham miners, rather than being an heir who could trace her family back through generations of aristocratic colliery owners was, allegedly, a source of huge amusement to William's well-connected mates.

Presumably these same flowers of the British establishment can trace their own families back to the days when their predecessors sold enough groceries to the royal household to enable them to purchase a title (or possibly just sold their comely daughters to a minor princeling instead).

On that basis it wouldn't pay Prince William to look too deeply into the roots of his own family. The once-lowly Spencers originally made their money as dodgy suppliers to Henry VIII (yes, horror of horrors, they were "in trade") and I'm not at all certain that a bit more recent digging on the extended Mountbatten side of things wouldn't turn up something nasty wearing a Swastika. (And I don't just mean Prince Harry).

If the whispers are true, Kate's parents have, unfortunately, committed the unforgivable sin of being middle class and as such have become the butt of those whose great grandparents were fortunate enough to manage to buy their way out of the suburbs.

One newspaper report last weekend suggested that Carole Middleton's use of words like "toilet" and "pardon" was a cringe-inducing source of merriment to William's "circle".

Well, in my book, there's nothing less classy than making fun of someone because they are not as well connected, as well bred or as rich as you - but perhaps I just don't move in the right "circles"?

When Prince William seemed to signal that Kate Middleton was the woman he intended to marry, this young man instantly rose above the recent years of scandal, indignity and humiliation that have dogged the royal family.

In choosing a nice, intelligent, pretty and largely unaffected girl as his partner, he almost convinced us that he was a normal bloke after all.

After four years I think the British public was right to start wondering if it should be digging out the union flags and booking a place in The Mall. This was a wedding we all wanted to see.

If William had any inkling that Kate was not "the one" he should have called a halt to this charade long ago, because in all likelihood he has now ruined her life.

Royal years are not like human years. It's a bit like those legends where unsuspecting mortals are lured into the world of faery for what seems like a day, only to find that seven years have passed when they return.

Behind the enchanted doors the bewitching ball continues, but in the real world things have changed irrevocably, leaving the mortal isolated and confused.

Kate Middleton had put her life on hold for William and acted impeccably in the face of the most testing circumstances. It was only recently that she made an official complaint about press intrusion, despite the fact that the paparazzi had been staking her out for months.

All the evidence suggested she was definitely being groomed for the role that seemed rightfully hers.

Just where she will go now and what she will do next should be a matter of real concern to the royals. Having opened the door to their gilded world and exposed her to its darkness along with its glamour they should take pains to ensure that she doesn't end up as damaged goods.

I sincerely hope that Prince William finds himself a worthy replacement for Kate Middleton, rather than some tiny-brained, neurotic, aristo totty whose mother doesn't use the word "toilet".

And I also hope he doesn't look back at April 2007 as the time when he threw away something that could have become the brightest and best of the crown jewels.

Writing as a Catherine, I was quite looking forward to the days when I could say that I shared my name with the Queen.