ROBERT HARDMAN: Camilla looks like Prince Philip and thinks it's time for KBO! The past few days have shown us that she is King Charles' 'rock'

With both the King and Princess of Wales recovering from hospital procedures, and the Prince of Wales taking time off to care for three young children, the monarchy has rarely felt so short-staffed.

We've heard a lot about the arguments for a 'downsized' monarchy in recent years, but for now this is starting to look alarmingly thin.

However, this is an institution that has always had to adapt and evolve to the demands of the moment – ​​and on this occasion Queen Camilla comes to the fore.

She is described by many (including her own family) as the king's 'rock'.

It's the kind of award that will make her roll her eyes.

But as the events of recent days have shown, Queen Camilla is the essence of the old war mantra of 'keep calm and carry on'.

Despite the latest absence from the royal frontline this week, the show has remained firmly on the road.

The Princess Royal has toured Cheshire, the Duke of Edinburgh has toured one of the most remote stretches of British territory in the world – St Helena – and the Duchess of Edinburgh has visited charities and schools in and around London.

Queen Camilla leads the way and when she doesn't have to care for the recovering monarch, she sticks to her schedule as planned.

January is always a quiet period on the royal calendar, but there is still plenty happening behind the scenes.

It's a time when the Royal Family and their officials plan the next six months of official duties and catch up on correspondence. Queen Camilla has also carried out a number of assignments under the radar.

A core part of her work is campaigning for victims of domestic and sexual violence. It goes without saying that many of these meetings take place away from the cameras.

Meanwhile, her public engagements included Wednesday's visit to Maggie's Cancer Support Center at the Royal Free Hospital in London.

It's a charity she knows very well, having been chair since 2008, and there was no question of letting it go.

She knows full well how much effort goes into organizing a 'normal' royal engagement – ​​the invitations, the security, the sweeping and cleaning and polishing of shoes, the fresh coat of paint, the 'reconnaissance' by the vanguard team of the Palace and the local Lord Lieutenant and the media arrangements, not to mention the catering.

People will have been looking forward to the big day for weeks. It's not just about meeting a member of the royal family. It's the feeling of national recognition for the entire team that creates the extra buzz.

This week I was one of a number of writers, illustrators and bookbinders invited to Windsor Castle by the Queen. We had all contributed to a new collection of small books for Queen Mary's Dolls' House.

Exactly one hundred years earlier, hundreds of authors and artists had created works for the astonishing library that is the centerpiece of the world's largest dollhouse. The Royal Collection Trust decided to update the collection in honor of the centenary and the Queen herself defended the initiative.

Promoting both literacy and literature has long been a core focus of her work. It was clear how much care had gone into this latest venture.

Everyone involved was invited to a reception in the Waterlook Room, thanked personally by Her Majesty and then given a special tour of the dollhouse and the treasures of the Royal Library. Everyone went home not only feeling like their efforts were recognized. We felt privileged to play a role, however small, in adding to a historic piece of our national heritage.

As a wise old private secretary to the late Queen once said of the monarchy, 'we are in the happiness business'. That's why the royal family understands how important it is to keep that show on the road.

Witness the royal response to Covid.

The pandemic seemed to be a serious challenge for the royal family, as their entire raison d'être is outward interaction with the public, in keeping with the late queen's mantra: “I must be seen to be believed.”

Yet the monarchy quickly mastered the art of online engagement. In the end, we saw Elizabeth II as regularly as before, but heard her even more.

This was because many of her audiences at charities, regiments or diplomats – who previously would have been captured only with a photograph and a mention in the Court Circular – were now shown online.

In my new book, Charles III, I have written extensively about the key role played by Queen Camilla. It's one that has emerged in recent days. And it's one that gives seasoned royal watchers a sense of deja vu.

As I say in the book: 'Her determined decision not to be the star of the show but the supporting act, the cheerful adherence to KBO's Churchillian doctrine [‘keep b*******g on’] the ability to bring a levity to a stifling situation, the deep love of books and the deep-seated attachment to the armed forces, the default use of plain language over jargon – all were hallmarks of the previous monarch's consort.'

The late queen called Prince Philip her “strength and fortitude.”

I suspect the king would say much the same about his 'stone'.