Prince William and Prince Harry: The persistent royal rift

This isn't a regular sibling fallout. It is a deep-rooted fracture filled with anger, resentment and a total loss of trust.

And much of it has played out in public.

The Prince of Wales remains in no mood to forgive and forget. The hurt he feels lingers.

"William is very stubborn," a family friend told the BBC. "To feel cheated by your own brother has been painful. He can't just put it behind him."

But in his interview with the BBC last year, Harry offered a different view.

"I would love reconciliation with my family. There's no point in continuing to fight any more."

The problem for Prince William now is proximity. Harry will be in the UK within two weeks, probably a short drive away from Windsor where William's family lives.

There will be pressure on the elder brother to take the lead, ease the pain and just make up with Harry now the siblings will be living in the same country.

"I think William doesn't care about the pressure to reconcile," said royal author, Valentine Low. "If he doesn't want to reconcile with his brother because of the things he's done, the wrongs that he feels Harry's done to him, he's not going to reconcile. But it does improve the chances I think."

Former editor of The Sun and presenter of the When it Hits the Fan podcast David Yelland said: "This is one of the biggest news stories in the world: the schism between William and Harry. Until these two brother get together or show us there is a rapprochement that story is going to make it very difficult."

He told BBC Breakfast: "Every single thing they do, where ever William goes, he will be asked about this because Harry is back in the neighbourhood.

"We don't need cuddles, we don't need posed-up photos, we just need a briefing that they have met. This is a real PR crisis for the Royal Family. William has to reach out, if he doesn't we are going to be talking about this every day for years and it's going to become a reputational threat."

The Prince of Wales will prioritise his public work in the coming months and try not to get drawn into the drama around the UK return of the Duke and Duchess of Sussex.

Several people from organisations who have worked with Prince William told BBC News of their desire to support William and help avoid Harry and Meghan becoming a distraction.

One source, who has worked on charity projects with the Royal Family, described wanting to protect the future King.

"This is a hard situation for him full of emotion and anger and we will support him," the source said. "It is really important for me to ensure that any work we do with William will be focused on making a positive change and won't be affected by the Harry and Meghan drama."