The shared presence on the Buckingham Palace balcony of the Duchess of Cornwall and the engagement ring worn by William’s mother dispels memories of rift and retribution for ever, says Patrick Jephson.

What a day. To see and hear William and Catherine take their vows was a privilege made no less special by sharing it with an extended congregation of a billion or so. As a wedding production, this one surely scored as high marks for technical merit and artistic interpretation as any in Westminster Abbey’s history. With their own eternal beauty, the familiar words reached out to our hearts and in return our hearts reached out to the young couple whom, despite their familiarity, it was as if we now saw anew.

We can see other things anew as well. The enduring strength of the great institutions of Crown and Church, Parliament and the Armed Forces – all now visibly transferring to the care of the rising generation. And who could fail to see anew the debt we owe the Queen and the Duke of Edinburgh, whose presiding parental role gives a whole new meaning to the idea of growing old gracefully.

Grace was a word and a gift that kept coming to mind, especially when attention moved from the solemnity of the Abbey to the jubilation of the Mall. For the first time in nearly 20 years, Diana, Princess of Wales’s engagement ring returned to the Buckingham Palace balcony. To its lustrous blue eye, the view of cheering crowds must have been reassuringly familiar. Poignant, too, if you recall its first visit to this place. Looking slightly to its right, however, it would have spotted something new and probably – in that location – rather bewildering: the distinctive silhouette of the Duchess of Cornwall, elegant in cream and aqua.

The symbolism is as deafening as the roar of yesterday’s immaculate fly-past. The mother whose name has seldom been heard in polite royal circles for half of William’s lifetime is now back on the approved list. Even more firmly on the approved list, and in a more substantive form, is his stepmother. For those who like their gestures nice and clear, yesterday saw both women publicly reconciled in a way that brings nothing but credit to William and his bride.

A big family occasion is a great opportunity for such healing initiatives. We can guess that few will have been more pleased than the new Duchess of Cambridge. Her experience as a child in a happy family will surely bring sunshine to the sometimes gloomy palace corridors that are now part of her world. The Windsors have a not entirely undeserved reputation for nursing grudges – sometimes even against their in-laws. So if his wife has helped William demonstrate the benefits of reconciliation, then everyone – but mostly he – can be the happier for it.

Of course, reconciliations seldom take root unless the original perceived offence has been purged. An honest acknowledgement of past failings is essential. After all, if bygones really are going to be bygones, it helps to have some agreement about what’s to be sent to life’s great compost heap of expended emotion.

I remember a fraught afternoon in Diana’s cheerfully cluttered, flower-scented sitting room. It was late 1995, more than three years after her formal separation from the Prince of Wales. William and Harry were at boarding school. The matter under discussion was anything but happy.

With a look I had come to dread – partly truculent and partly apprehensive – my boss was waiting for my reaction to the bombshell she had just exploded in my overcrowded brain: she had secretly recorded an interview for Panorama. It was going to clear the air, set the record straight and generally put us on the path to a less complicated future. And I was not to worry.

But I did worry. I also tried to find the right words to persuade her that an olive branch might be a better offering than what I guessed would be a one-sided repetition of past grievances. The moral authority she would have gained from such a self-assured and magnanimous coup would have scored a knock-out in the unedifying contest for public sympathy in which she and her husband seemed permanently trapped.

She was not to be persuaded – or perhaps I just didn’t find the right words. Instead of reconciliation, a conclusive twist was added to the downward spiral of relations with her in-laws. For the remainder of her life, she moved inexorably away from the royal structure which, for all its faults, was always reliably protective.

Protection, we can be sure, is what William wants for his vulnerable new bride. Protection especially from the unhappiness, he must feel, that was so avoidably piled on his mother’s slender shoulders. Since the cornerstone of such protection will be a secure marriage – in which success and failure are experiences to be shared rather than triggers for distrust – much of the responsibility will lie in his hands.

An even-handed and relentlessly polite relationship with the media will be the best protection against the dangerous illusion that the press are an enemy to be bested at every turn. The extent and tone of media coverage of this event should remind us of its power to unite as well as divide.

Protection from physical harm doesn’t need any elaboration, except to remember that Scotland Yard’s finest are better than any alternative – a point well underlined by yesterday’s faultless security operation.

Protection from the loneliness of the royal road and from the corrosive search for “relevance” is best secured through a consistent programme of low-key hard work, with all the job satisfaction that royal status can unlock.

Most important is to find protection from the self-doubt that seems an inevitable by-product of being – even theoretically – always in the right. The adulation that’s just been ramped up 10 notches by the wedding can play havoc with the most seasoned public figure’s sense of proportion. The best protection might often be found in remembering that a moment of royal humility can achieve more than a week of icy royal looks. It really is better to be loved than feared. Without that regular acquaintance with humility, there’s little chance of seizing those all-important reconciliation opportunities.

Even if only in the form of an engagement ring, William’s mother has sealed reconciliation with the woman she had reason to hold responsible for her cruelly dashed marriage expectations. In the words of William and Catherine’s own prayer, there could be little better example of “what is real and important in life” than this evidence of grace. That William has had the courage and wisdom to heal such a wound perhaps promises more for his eventual reign than anything else we saw in the wedding celebrations.