The "heir and the spare" is how Princess Diana once referred to her two sons, Prince William and Harry, neatly capturing what all this royal business is about.

Kate Middleton will not be judged on her looks, her accomplishments or even her middle class as against bluebood ancestral lines.

No, like a good stud mare, she will be judged by whether she produces preferably a few young colts to make sure the blood lines continue.

Prince William after all is a product of what Warren Buffet has memorably called the "lucky sperm club," the inheritor of wealth, class and title, none of which he earned for himself.

His main job is to ensure that he passes on the royal bloodlines, created in his case, through his grandmother Elizabeth who became queen only after the male-in-line, Edward, began to show Nazi sympathies then ran off with an American divorcee who shared his Aryan philosophy.

Prince Harry recently paid nice homage to his ancestor by dressing up as a Nazi at a party.

Of such events are great dynasties born.The past is all elided over and the future comes packaged in a box called hype and hyperbole.

We will learn all there is to know about the prince and his bride-to-be. Sadly, he exists mainly to fulfill the fantasies of a nation. she now exists to reproduce.

He has no real power, except to attract tourists in their millions every year to a grown-up version of Disneyland.

I passed by Buckingham Palace on a recent visit to London and was astounded by the waiting thousands there for the changing of the guard.

Like so much in Britain these days, it is all about symbolism and play acting, not the real thing.The days of imperial power are long gone but the fantasy machine will be greatly enhanced by this royal wedding.

As for the average Briton, he and she will continue to struggle in these harsh economic times, but many will be happily distracted by the circus around the royal wedding of the future king.

When the confetti is swept away however, the harsh realities will resume. It will take far more than a royal wedding to halt the decline of the most famous empire.