AN WILSON: This is a potential constitutional crisis that is going to place an immense burden on William

When a 75-year-old man is told he has cancer, then dread and hope fight a battle, both in his own heart and among his family. After Buckingham Palace announced King Charles was suffering from cancer, we too felt these emotions.

Yes, there appears to be a new openness about the illnesses suffered by the royals, but in some respects there is still the old caution. We were not told the nature of the cancer.

What we do know, however, is that we would not have been told at all were it not for the fact that the doctors are worried.

After Buckingham Palace announced King Charles was suffering from cancer,  the nation felt the same sense of dread that Queen Camilla and his family will be experiencing  

Of course, everyone of good will wishes the King a complete recovery. And, thanks to the advances made in cancer treatment in the past decades, we all know cases where recovery from the disease is complete. Nevertheless, this is not simply a sobering moment in the history of the Windsor family. It is a potential constitutional crisis-point.

How quickly events move on and life changes! At Christmas, we should all have said that the King and the Royal Family were on a bit of a roll.

He had defied all the gainsayers (me included) who thought he would make a hash of being a constitutional monarch, because of his strongly-held views and his hyper-sensitivity to criticism. In fact, after that initial moment of irritation with a faulty fountain pen at the Accession ceremony, King Charles has been an absolute model of how to fulfil this role.

He seems consistently dignified and good-humoured. His continued, and justified, concern for the environment and the future of the planet has not interfered with his political role in the slightest. His demonstrations of British ‘soft power’ abroad has been palpable. The visits to France and Germany were triumphant personal successes.

The Princess of Wales needed medical treatment, and now the King. It’s impossible not to feel that the last two weeks will have added years to Prince William ’s life

His Queen – good-humoured, everlastingly well-mannered, a ‘brick’ – has grown in popularity. It really looked as if the monarchy had entered a new golden age. And the darker clouds in the sky – such as the possibility of Prince Harry making an ass of himself on some American chat show or in the law courts – somehow seemed less worrying. With such a rock-solid monarchy, we could even face the further exposure of Prince Andrew’s friendship with the notorious Jeffrey Epstein.

Moreover, as well as having a popular King and Queen, we had a Prince and Princess of Wales who could do all the ‘fun stuff’. While the King could enjoy opera and ballet, they could meet rock stars and actually know who they are. Kate could be seen playing rugby and other sports rather better than most chaps.

Then the Princess of Wales was hospitalised. And now the King. And it’s impossible not to feel that the last two weeks will have added years to Prince William’s life. He is now faced not only with looking after his young children while his wife recovers from abdominal surgery and a 14-day stay in hospital. He is also much, MUCH closer than anyone could have guessed to having to take on the role now occupied by his father.

This is not to be ghoulish or morbid. It is the simple fact of the case. Although it has been clearly stated, in the announcements from the Palace, that the (much smaller number) of working royals will step in to act on behalf of the King for engagements, everyone knows that there is only one person who can, in the most extreme case, take the King’s place, and that is his heir.

The situation places a huge burden on Prince William, at a time when he is worried about his wife, and when the devastating feud with his brother Prince Harry is still unresolved

This places a huge burden on Prince William, at a time when he is worried about his wife, and when the devastating feud with his brother Prince Harry is still unresolved.

Many people had their doubts about Charles during the long years he waited to take on the role of King. But in all those long years, he was learning. And, whatever the nature of his relationship with his parents, he had them not only as an example, but as constant companions who could point out to him how the job was done.

To a certain extent, the role of the constitutional monarch is very simple. The monarch, as the symbolic head of state, has to keep the show on the road, and that’s it. But, as Queen Elizabeth II and Prince Philip knew, after decades of experience, there are many hazards along the way. The fact that Charles has turned out to be such a surprisingly popular and successful monarch is partly a tribute to him – of course it is. But it is also a tribute to his parents.

William has had very much less time to learn from his father. And unlike Charles, came from a broken home. He is still carrying the scars of that, and of his everlastingly missed mother’s legacy.

It was in part a benign legacy, from Diana both Harry and William have inherited and learnt a spontaneous awareness of those less fortunate than themselves, a lack of stuffiness and a sense of fun. She was a wonderful woman in so many ways but she thought her job was to be Queen of Hearts, a sort of royal rock star.

These qualities, which are wonderful ones for any public figure to have, are not in themselves enough to fulfil the role of a constitutional monarch.

We have been told that Charles, during his treatment for cancer, will continue to read through the red boxes which, with relentless frequency, appear on his desk day by day. We have been told that he will continue to hold weekly audiences with the Prime Minister.

These are the core tasks of the constitutional head of state. William has no experience of them, and they must be, apart from anything else, both boring and taxing. Successive prime ministers of all political colours, used to say how much they learnt from their audiences with Elizabeth II, partly because her memory went back so far and she had an unrivalled knowledge of world politics.

William is going to have to learn fast – whatever the medium-term prognosis of his father’s illness may turn out to be. And he is going to have to learn these lessons in difficult circumstances, in the short term without the carefree, perpetually smiling Kate as a bouncing Tigger by his side.

For it is not all about being seen out and about glad-handing in public, although that is an important role of the monarch. Queen Victoria was an excellent constitutional monarch even though she led a life of almost total seclusion during her long widowhood.

She went through not only all the red boxes, but often the Cabinet papers as well and she got to know prime ministers and Cabinet ministers very well. By the time of her Diamond Jubilee she was the most popular monarch in history.

More than being on constant display you need a sense of what the job is to be a successful monarch. The job, so difficult to define, is fatally easy to get wrong.

Charles, like his mother and father, has always known that the real business was what went on in private – with the prime ministers and the red boxes, and the visits of foreign dignitaries, especially those of the Commonwealth.

We live in perilous times, with the world seeming to be balanced on the verge of wars in Europe and the Middle East. History in the past century has shown that constitutional monarchy is a stabilising, strong influence on events if it is properly understood. In the era of the fascists and the Soviet Union, Edward VIII did not understand it, and it looked as if the monarchy would go under. Only when George VI and Queen Elizabeth (later the Queen Mother) guided it back to its modest but stabilising role did it come into its own again.

This tradition is strong, but vulnerable. I for one do not envy anyone who might be obliged to take it on in the modern world, and my heart goes out to Prince William as his father undergoes this course of medical treatment.