Sarah Vine: The Princess of Wales’ cancer diagnosis means she must focus on herself to make a full recovery

Life can be so cruel. As if the King having cancer weren’t brutal enough, now this. The news that the Princess of Wales, aged just 42, is also battling this awful disease is almost too much to bear.

Hasn’t the royal family suffered enough in recent years? The death of Prince Philip and its great matriarch, Queen Elizabeth II; the tragic and embittered departure of the Duke and Duchess of Sussex; the King falling ill so soon after the Coronation, just as he was getting into his stride.

It’s been one hammer blow after another. And yet it seems the Fates are not yet done with the House of Windsor.

The Princess of Wales? That is the cruellest twist of all.

Her video message to the nation was stark in its simplicity and sincerity. Sitting on a garden bench and wearing a low-key striped top and jeans, she looked a little pale, but still managed to smile. A couple of times, she dropped her gaze, and a wave of sadness briefly crossed her face. It’s clear that, as she said, it’s been a tough couple of months.

How desperately unfair this is. Not only is she a woman in her prime, she leads an exemplary lifestyle. She ought to be the last person facing a serious illness at her age. But then cancer, let’s face it, respects nothing and no one.

She is also a mother to three young children: George, ten, Charlotte, eight, and Louis, five. They will be her utmost priority now: shielding them from the public reaction to her illness and reassuring them of the most important thing of all - that Mummy is going to be absolutely fine.

Nothing is more frightening for a child than seeing a parent unwell. I have had friends who have faced similar situations – and the guilt and worry are intense. In particular, it’s incredibly hard undergoing exhausting and debilitating treatment while putting on a brave face. But it’s what you have to do, even when you are feeling sick to your stomach and can barely lift your head off the pillow.

Life must go on for the Waleses’ children in as normal a way as possible. A degree of seclusion is undoubtedly best for them all now. As the Princess said in her poignant video message: ‘It has taken us time to explain everything to George, Charlotte and Louis in a way that is appropriate for them, and to reassure them that I am going to be OK.’

She looked so sad as she spoke those words, and so terribly fragile. Poor kids. It’s a lot to deal with for any child; given the added pressures they face, these difficulties can only be redoubled.

We should also spare a thought for William. Both his beloved father and his adored wife are stricken with the same affliction, and he can’t very well turn to his brother Harry for support — not as things currently stand, at least.

Perhaps that will change. But in the meantime, the two figures he most relies on for support and advice are both indisposed. And Granny, who was always such a source of reassurance and wisdom, is gone. It must be a deeply unsettling time for him, too.

But the person who needs the most care and attention is, of course, the Princess. Like most women in her situation – a busy wife and mother with a demanding role of her own – I suspect she may find taking her foot off the pedal and allowing herself to be looked after a challenge. Women like her are not necessarily used to putting their own needs first - but those around her, who love her, must insist.

Girlfriends of mine who have had run-ins with the big C have had to learn to let go, to get used to the change of pace. And it’s not always easy, especially if you are the sort of woman who, like the Princess, demands of herself the highest standards. Challenging as the treatment can be, it’s not always the physical side effects that are the hardest to cope with; the mental ones can be considerable, too.

For a woman as dynamic and active as Kate, staying still won’t be easy. There is something of the eternal head girl about her, always first to put her hand up to volunteer, never one to shy from responsibility. She has always been exemplary in the execution of her royal duties, and since the death of the late Queen and the departure of the Sussexes she has taken on more than her fair share. She is such a dutiful, reliable person, no doubt she will be worried about letting everyone down.

But she mustn’t. If there’s one thing that the past couple of weeks have reinforced, it’s the sense that she is held in towering estimation by the British public. In fact, I’d go so far as to say that they adore her. It’s abundantly clear that in the 12 years she has been married to William (and the near-two decades she has been in the public eye) she has truly earned their respect. Unlike some others, she has never expected or demanded anything. She has simply worked hard and consistently, winning over hearts and minds little by little.

That is why she is such a precious asset to the royal family. She occupies a space somewhere between the late Princess Diana and the late Queen herself: a unique combination of the former’s beauty, glamour and warmth and the latter’s stalwart sense of duty and strength of character.

This diagnosis is not only a blow to the royals as a family, but also to the institution itself, which has rarely seemed more vulnerable.

But she will get through this. As she said herself, the treatment is ‘preventative’, meaning that the cancer has been caught early. And she has all the help and support she needs, not only from her excellent medical team, but also no doubt her own parents, the redoubtable Middletons, and the King himself, who said last night that he is ‘so proud’ of her.

In her video message, the Princess movingly said Prince William had been a ‘a great source of comfort and reassurance’. She has been his rock and anchor during their marriage; now he will be hers. I have no doubt that they will come through this crisis even closer than before.

All the Princess needs to do now is focus on allowing herself the space and time she needs to make a full recovery. Truly, if goodwill and fond wishes were a cure, she would be better already. All our prayers are with her and her family.