Currently, the Duke of Sussex remains in California with his chicken coop. His earning potential seems to lag behind his ambitious wife; and as time progresses, even Meghan’s ability to generate income from television work will diminish. Eventually, the couple may become less and less fascinating to the general public, shifting attention to the next generation.

The harsh reality of being a balding, former royal appears to trouble Harry—so, as the Mail on Sunday unveiled with those striking images of the King’s aides meeting the Sussex staff, he’s now attempting a return, hoping for his father’s forgiveness for his grievous errors: from his petulance and allegations of racism on the Oprah Winfrey show to the ghost-written and controversial memoir, Spare.

But now what?

When Harry and Meghan visited the late Queen a few months after their wedding, proposing to be part-time royals, they were dismissed with a firm refusal. They had to be fully in or out. You can’t be somewhat royal any more than you can be somewhat pregnant.

Time has passed, however, his grandmother is no longer with us, and Harry must now be wishing: if only the Royal Family could accept him back into the fold, at least in part, he might regain some of the prestige he so arrogantly threw away.

He was popular with the public before his marriage and the awful rows with William and Charles that followed it. He was a brave soldier, who looked good in uniform and saw active service. He was a cheerful-seeming ‘playboy prince’, with what seemed like a natural empathy for people.

His Invictus Games, an Olympics for military personnel overcoming huge physical challenges, not only did a great deal for the disabled, but inspired the population at large with the knowledge that human beings can, when pressed, achieve mighty feats.

Brave veterans who have lost legs and arms in the service of their country can go on to become elite athletes. Can a comparable miracle occur when two brothers are confronted with a seemingly irreconcilable feud?

Although the present ‘peace talks’ are seemingly being conducted between the King’s haughtiest flunkies and Harry’s sharp-elbowed American team, the real challenge is going to be effecting an entirely different reconciliation: between Harry and his brother.

The overwhelming likelihood, of course, is that the King, now 76 and still being treated for cancer, will predecease his forty-something sons. All those who have William’s best interests at heart – and this must include everyone who wants a bright future for the monarchy – must be begging him to extend some kind of olive branch to his wayward, disloyal and maddening younger sibling, to say nothing of Harry’s manifestly difficult wife.

If Harry and his father find a way to be reconciled, that would be a fine thing. But it is the next reign – that of William V – that is likely to be longer and of far more consequence.

Consider one possibility. William offers his brother an olive branch and he accepts it. Harry and Meghan can then perhaps achieve something close to what they originally asked for – being ‘part-time royals’. They might resume occupation, for part of the year at least, of some grace-and-favour mansion in Windsor Great Park, with additional houses, perhaps, in London and Scotland.

They can support British charities, perform royal duties and, in return, enjoy taxpayer-funded bodyguards and, who knows, even some recompense for being ‘working royals’.

Both of them – even their enemies would admit – have some charm, while the camera loves Meghan almost as much as she relishes it.

William and Harry would not even have to spend much time in one another’s company, but they would be doing the civilised thing. If Harry knew that he had to attend an Armistice event in the Royal Albert Hall, or a Regimental Dinner, or the Chelsea Flower Show with Meghan, he simply would not be able to go on leaking malice in private and whingeing in public.

Of course, the quid pro quo would be that they would have to abandon some or all of their commercial ventures, which they – and especially Meghan – might not countenance. It would also rule out any of the Duchess’s political ambitions, if she has them (she has made her Democrat leanings abundantly clear).

But if such a deal could be struck, it would only enhance the strength of the monarchy and the popularity of the Royal Family.

Does this seem realistic? Not remotely.

The far more likely alternative, it seems to me, is that William and Kate can never find it in their hearts or brains to effect some kind of reconciliation with the Sussexes. Everyone would understand this – after the truly dreadful indiscretions of Spare, and the drip, drip, drip of spite and venom that has come from the Sussex camp since the great sundering that was Megxit.

Meghan, I suspect, will never want to return on any extended basis – perhaps even at all – to this damp and diminutive island. Who knows what glittering future she imagines for herself? Kate has been through hell recently, given her health troubles, and would probably be glad never to see them again. William, rightly, stands by his wife.

But what the Prince of Wales and all defenders of the monarchy must realise is that if Meghan and Harry are left outside – bored, disgruntled and unloved – it is inevitable that they will grow increasingly bitter. Whenever they feel the need for cash, they will give another interview, or write another book designed to inflict personal wounds on the family – reminding everyone of their status as its shrivelled offshoot.

And that spells disaster. History shows that fractured dynasties do not survive. A new generation, reared on tales of exile and racism, may find their own axes to grind.

It would be miles better, then, that the Sussexes be brought in from the cold. Both sides should be seeking, not only diplomatic and political help, but personal counsel. This was a pair of brothers who, from earliest childhood, were facing the broken marriage of their parents; their mother’s untimely death; unfounded and scurrilous speculation about Harry’s paternity; and generally a gnawing inferiority complex on Harry’s part – some of it understandable. Who wouldn’t feel inferior, after all, to the heir to throne?

Neither of these pampered lordlings is an easy person: and neither can ever hope to lay aside all their childhood ghosts. But they can be taught to recognise them.

If William does refuse to make peace with Harry, the Sussexes will not go placidly into a dignified Californian silence. They will seethe and seek revenge. Skeletons in the family cupboard, much better locked up with the moth balls and empty coat hangers, will come dancing out – probably at some unforeseen moment when the monarchy looks even less robust than it does today.

Let me be clear. The institution that has served our country so well is only ever as strong as the person who wears the crown. This row between the brothers is festering, furious – and could prove fatal. When Charles vacates the stage, as one day he must, and William is anointed, a middle-aged brother in exile, on non-speakers with the sovereign but with a potential audience of billions, could do incalculable damage.

It’s no exaggeration to say that this row could one day begin the process that leads to a republic. And that could come much sooner than we royalists might like to admit.