I’m worried about Kate and William. Not about the wedding. That’ll go off without a hitch, and give Brits and royal watchers just the jolt they need to stay interested in the increasingly irrelevant institution that is the monarchy.

No, I’m worried about the future.

I don’t think anyone is aware of what a perilous position Kate and Wills are in. Anyone except me. Right now, everyone except die-hard anti-monarchists are caught up in a gauzy love affair with the young nubiles. What’s not to love? They’re young, healthy, good-looking and haven’t yet been recorded referring to each other as a feminine hygiene product. So far, so good.

But the next five years are crucial. And I fear Kate and William are headed for trouble.

After their wedding on April 29, they’re packing up and moving to a tiny cottage in Northern Wales (after a brief stomp about balmy Scotland). William will spend his days as a search and rescue pilot with the RAF, and Kate will be at home, blow-drying her beautiful hair and not working. (Feminists of the world, Ms. Middleton is not interested in a career. Get over it.)

Good on them, says Penny Junor, the author of Charles and Diana: Portrait of a Marriage and The Firm: The Troubled Life of the House of Windsor.

"William and Kate need some time to be a normal couple and the minute they get on to the circuit good and proper, all sense of normality will vanish," Junor wrote me in an email. "If I was advising them on how to spend the next five years, I would say: enjoy being together, allow the relationship to strengthen before too many strains are put on it, start a family and enjoy the children and be with them as much as possible… and gradually ease themselves into royal duties."

It’s sensible advice for a young couple.

Trouble is, they’re not just a young couple. They’re the future of the monarchy, and they’re going to consign themselves to total irrelevance up there in Wales. Right now, they’re appealing because they promise to inject the monarchy with life and energy. And yet, what’s the first thing the couple wants to do with all that newfound youth and energy?  Hide it away in a drafty cottage. It’s a disastrous plan.

They should use the burst of goodwill that this wedding has ushered in and revitalize the monarchy. Princess Diana worked tirelessly to raise awareness of land mines, AIDS, leprosy — where there was misery, she was there. William should follow in her footsteps — ditch the piloting, pick 10 causes that need attention. I have some ideas — sex trafficking, rainforest destruction clean water to prevent disease — but he hasn’t called.

The reason people mock the royals for being decorative and irrelevant is because so many of the royals behave in a decorative and irrelevant fashion. Kate and William could diverge from this tiresome path. The trouble is, I don’t think they will.

Good manners and deference to his large-eared padre may stand in the way. "William is NOT the next King of England. Prince Charles and Camilla would feel very upstaged and angry if William and Catherine started various tours, and got too overly involved in overseas work at this early stage," Una-Mary Parker, romance novelist, royal watcher and ex-Tatler columnist, told me via email.

This doesn’t seem fair, considering nobody seems to want Charles to be King. Opinion polls following the news of the royal engagement showed that 64 percent of the British public were in favour of William and Catherine succeeding to the throne, while less than one in five wanted the crown to pass to Charles and Camilla.

If public opinion became feverish enough, Charles would be taken into a dark room and pressed to step aside. He could then announce that he had decided not to become king because he wanted to live a private life or some other such hogswaddle, and then Wills would get the crown.

Best case scenario: William and Kate spend the next few years winning the hearts of the British people with Diana-like crusading, Charles is quietly asked to step aside and William dons the crown instead.

Let’s hope they get it right. It may be the monarchy’s last chance.