Practice makes perfect for Kate, the Royals' new kind of princess

After eight years of dating and much of that time spent living together in comparative seclusion from the long lenses of the world's media, a wave of sentimental slush is already breaking over their heads, and they haven't even named the date yet.

Might Prince William and fiance Kate Middleton already be wishing they'd held out even longer before announcing their engagement? The lost idea of enjoying just one more Christmas and one more skiing holiday as boyfriend and girlfriend may seem such a tempting one this morning.

But, as Prince Charles said yesterday, while expressing delight over next year's wedding: "They've been practising for long enough."

At some point William and Kate had to get on and announce a wedding – or call the whole thing off. "Practising" isn't quite like the real thing, though, and not a viable long-term plan if your surname is Wales. But maybe part of Prince Charles regrets that he and Diana Spencer did not have time to practise before tackling the choppy waters of married life aboard a royal yacht 29 years ago.

Practising without the pressure of actually being engaged and the most talked-about British marrieds since Charles and Diana was a thoroughly 21st century start for the William and Kate, who met and shared accommodation while studying at St Andrews University – which prides itself not only on its very high academic standards but also on being the British university with the highest hit-rate of future spouses meeting each other.

University life led under the rules of a media curfew during the Prince's student years and, more recently, enjoying cosy evenings by the log fire, cooking for friends and taking walks in the hills around their Welsh cottage will not, however, have prepared Kate Middleton for the reality of what's about to happen to her.

There's a lot to get used to, even for a woman who's spent the last few years becoming increasingly involved with the Royal Family. No-one actually knows what it's like to be one of "the firm" until they are officially part of it, and by all accounts it's not for the faint-hearted.

In the short-term, Kate will suddenly have to find her voice in public, if only to thank well-wishers in the coming days. She'll have to accept, too, that everything from her skincare routine to the colour of her tights and choice of wedding dress designer will be endlessly speculated over; and then there's the strain of your wedding being not so much the expression of you and your fianc's tastes and desires, but an international spectacle constructed around royal protocol and tradition, a focus for the world's fantasy about an ordinary girl bagging and managing to marry a prince.

Since the unfortunate death of Diana, Princess of Wales, the cult of celebrity has moved more and more to soap stars, footballers and reality show contestants. But make no mistake, a real live princess whose husband will almost certainly be king and whose child may be a future monarch is always going to trump Jordan, Katie Waissell, Coleen Rooney and even Victoria Beckham. But will the world look back at the maelstrom that surrounded Diana and collectively decide to cut Kate a bit more slack? Will she be allowed to be herself – by "the firm" or by any of us?

While the bubbles are still fizzing in the Champagne, one of Diana's closest former aides warned that Kate must quickly establish what her future role is to be if she is not to face the same problems encountered by Diana all those years ago.

Patrick Jephson, who was the Princess's private secretary, urged the new royal fiance to concentrate on the practical side of her life with the Windsors.

"If they want her to be a wife, a pretty face, to keep quiet and stay in the background get that straight now, not in the future," Mr Jephson said. "If they want here to be more active and carry on the role, Diana-style, let's get that straight too."

He added: "She has to agree on her position, especially in relation to her future husband William. She needs to know what's expected of her. Is it going to be a joint operation? Does she have the necessary resources in terms of people, guidance and experience? If you speak to people who were around when Diana arrived, nobody had a serious talk to her about what she was going to do. She made it up.

"She developed her own style and role, and in the end it got out of synchronisation with the rest of the household. Kate's not just going into a marriage, she's going into a business."

Duty, not her own career ambitions, must come first for the university graduate and one-time student, Mr Jephson said. "It's duty first. In this position, if you don't understand what your duty is, you're going to come unstuck."

Sacking spin doctors and following the Princess Royal's approach was among the key advice Mr Jephson had for Miss Middleton. "Take a vow of silence, then concentrate on building up your reputation for good solid work. If she gets on with the job, keeping her head down, working hard and not looking for sympathy, people will love her for it. If they think she's hiding behind spin doctors and there's an image being presented that isn't true, she'll be in trouble."

On how to cope with the endless "grip and grin" line-ups during royal engagements, Mr Jephson said: "If she has a good purpose for meeting the general public, she will feel that much more confident. If she thinks it's worth doing, she will find the job relatively easy.

One massive advantage Kate has over Diana is that she knows her future husband so much better than Diana knew Charles when she was approved as "wife material". Diana was a 19-year-old kindergarten teacher, a pampered but insecure young woman from a broken home, who'd had little experience of romance. While there's no evidence of Kate Middleton being a wild teenager, she is 28 years old now, has dated William for eight years, and has been very much loved by a solid middle-class family with parents whose relationship appears to have been a bedrock.

Mr Jephson gave a poignant insight into Diana's jittery state of mind the night before she married Prince Charles: "(Diana was told)... 'You can't back out, Your face is on the tea towels...'" He said that it was never too late for Kate. "Screw the tea towels. If you've got serious reservations, don't go through with it. It's such a public thing. If they don't get this one right, what's going to happen to the whole institution in the long run? If she was my sister, I'd tell her to get a good pre-nup."

Old-fashioned and slightly spoiled though it makes her appear, it's probably to Kate's advantage that she does not seem to have to any urge to carve out a separate career for herself, because its demands would almost certainly create tensions between herself and the Royal Family. She's had time to find out and absorb how the Windsors spend their lives and how seriously they take their public duties. Those like Princess Anne who get on with charity work, riding horses and avoidance of glitzy occasions manage to have some semblance of normality in their life, although the Princess Royal is only able to maintain such a low profile because she is not that close to the throne.

Being the spouse of a serving military officer will make huge emotional and logistical demands in itself, but Kate already knows about that. Unlike Diana, she seems to be a grown-up who knows what she's taking on.

So much talk about Kate, but not so much about William, yet like the children of many divorced parents, he probably has a deep-rooted yearning to create a strong, lasting marriage that will grow and sustain any children they may have. For all the privilege of his upbringing, the little boy inside the man almost certainly wishes he'd had some of the continuity offered by the Middleton family.

A lot has been spoken and written about whether the future of the monarchy will be "in safe hands" if William marries a commoner, and whether Kate Middleton has the toughness to take on the role that now seems to be her destiny. The indifferent observer can only watch, wish them well, hope that confident and poised Kate doesn't have to grow a rhino's hide, and hope too that the monarchy has moved on enough after its many disasters to see that marriage works best between equals and that the old firm should now bend a little to accommodate Kate rather than vice versa.