No wonder Prince William is looking so glum these days. He's running out of royals.

The return of Prince Edward and wife Sophie from their hugely successful State Visit to Japan serves as a reminder to the future king that when his time comes, there's almost nobody left to send abroad on these vital goodwill missions.

Once, there was a raft of royals who filled out the 25-yard wide Buckingham Palace balcony. Slowly one by one, they've drifted away.

And it's created a crisis for the times ahead.

The golden years are all but gone - for the time being. In 2011, there were twelve major royals and their families sharing public-facing duties. Between them they covered 3,874 engagements, flying the flag both at home and abroad.

But by 2024, the last figures available, the personnel had dropped by two down to ten - but the overall attendance figures had shrunk by almost half to 2,168.

The problem for William is that things can only get worse before they get better.

Prince William with the Princess of Wales and the Duchess of Edinburgh at the Duchess of Kent's funeral at Westminster Cathedral

A glum looking Prince William who seems to be running out of royals

The return of Prince Edward and wife Sophie from their hugely successful State Visit to Japan

The oldest royals - the Duke of Kent, 89, and Princess Alexandra, 88 - though maintaining links with their various charities and organisations, have effectively disappeared from view. Pictures of the Duke grieving at the funeral of his wife earlier this month were a reminder of his long length of service, but also graphically illustrated he can no longer play a part in the essential royal rituals of tree-planting, plaque-unveiling and ribbon cutting.

The same goes for Alexandra, while their cousin the Duke of Gloucester, 81, and his wife the Duchess, 79, are way past the national retirement age. Though they battle gamely on, they were never front-and-centre royals and go largely unrecognised.

Prince Andrew retired in disgrace in November 2019. Harry, together with Meghan, fled the coop in 2020.

The troops have left the battlefield, leaving their future commanding officer Prince William in despair. All that'll be left when he steps up to the throne will be him and Catherine, Edward and Sophie, and Princess Anne.

Public demand for the attendance of a royal to mark major and minor events up and down the country remains as high as ever. And though King Charles has responded well to his cancer treatment and is working away as industriously as ever, William knows - as every heir to every throne knows - that kingship is always just a heartbeat away.

It's clear from the various statements coming from Kensington Palace that William has formulated his plans for the future. But what do they include?

And - just as important from the public's point of view - what do they exclude?

Prince Andrew retired in disgrace in November 2019

Princess Anne carries out countless jobs on behalf of the Royal family

The answer, inevitably, is less contact with the public. And no amount of social media coverage can replace the lifetime's memory generated by a real-life meeting with a royal.

The future king-but-one, Prince George, won't be 18 for another six years. Add another three years for university, and that means he won't step up onto the public stage until 2034. Like it or not, he's born to serve - but there's no guarantee his sister Charlotte, 10, will become part of the royal circus - or kid brother Louis, now just seven. William and Catherine have been rightly protective of their children and one suspects they may leave the choice up to them when they arrive at adulthood.

Queen Victoria had nine children, her son Edward VII six, and his son George V five. For well over a century we've had more royals than you could shake a stick at.

When Queen Elizabeth ascended the throne in 1952, the royal line-up included husband Philip, the Queen Mother, Princess Margaret, the Duke of Gloucester, Princess Marina, Duchess of Kent - even the London bus-riding Princess Alice, Countess of Athlone! Earl Mountbatten, though not of royal blood, shored up the team.

Now there's a dire shortage. William, will be left with Princess Anne, 75, Prince Edward, 60, and Duchess Sophie, 60. Plus Catherine.

And that's it. Where's the young royal blood, once so freely available?

The future king could call upon his cousin Zara Phillips - by far the most popular of the 'non-royal royals' - but she has a successful business to run.

And as King Charles pointed out in relation to Prince Harry last week, you can't be half-in and half-out of the royal cadre - making money on the one hand and snipping ribbons on the other. And anyway, would Zara really want to give up the freedom of her glamorous freewheeling life she so clearly enjoys with adoring husband Mike Tindall?

Would Zara really want to give up the freedom of her glamorous freewheeling life she so clearly enjoys with adoring husband Mike Tindall?

Lady Louise Windsor, 21, who charms all who meet her and could be a decorative and useful asset to the royal team

Despite his father Charles's ruling that Princess Beatrice, 37, and Princess Eugenie, 35, should not be allowed to represent the royal family in public, William might have been able to reverse that decision - but then came the disgrace heaped on the House of York by the girls' parents Andrew and Sarah. In addition, with husbands who are hardly royal consort material - a property developer (Beatrice) and ex-bartender (Eugenie) - neither is likely to find much favour with the general public.

That leaves dark-horse contender Lady Louise Windsor, 21, who charms all who meet her and could be a decorative and useful asset to the royal team. But her mother Sophie, vastly protective of her daughter, is just as likely to want her to stay out of the spotlight.

Of Louise's brother James, 17, little is known of his character and personality or whether he'd wish to serve as a front rank royal - even if William wished it. Currently he's a pupil at Radley, the Berkshire public school.

King Charles once talked about the virtues of a slimmed-down royal family. Just now, it looks like a case of 'be careful what you wish for'.

How Prince William is running out of Royals