A renowned royal biographer suggests that Prince Harry is anxious about the possibility of being exiled from the UK when his brother, Prince William, ascends the throne.

The Duke of Sussex, 40, is said to have begun thinking about the future and is eager about mending bridges with his cancer-stricken father.

Earlier this month, his aides were seen meeting up with the monarch’s communications secretary for a top-secret meeting in London.

The gathering highlighted another facet of the ongoing tension, as the communications team for the Prince and Princess of Wales was absent. It was later discovered that they were not informed about the discussions taking place.

And royal author Tom Bower believes that the feuding camps have a long way to go before the hatchet is buried.

“Whether they’ll reunite during Charles’s reign depends on his lifespan. I wouldn’t rule it out completely, as I believe Charles wishes to reconcile with his son, but much will rely on Harry’s actions,” Bower told The Mirror.

“Harry is seriously worried that when his father dies one day, William will literally banish him and he will have no status in Britain at all. He will be persona non grata.”

Bower, who penned “Revenge: Meghan, Harry and the War Between the Windsors,” described the “Spare” author as “his own worst enemy.”

Elsewhere, the expert noted that while Harry is “desperate” to repair his fractured relationship with Charles, a royal reconciliation may not happen given the extent of the years-long rift.

“Harry needs a meeting with Charles to show he is part of the royal family and to establish his credibility in Britain,” Bower said, adding that the Invictus Games founder is “unpredictable.”

“But as long as the Palace won’t give him access to Charles, he can’t take the first step,” he went on.

“They suspect that the moment he meets Charles, he will use it to establish his credibility, because that’s what he desperately needs, and that’s also why he’s kept away.”

Follow The Post’s royal family live blog for the latest pics, news, exclusive details and more

The Post has reached out to the duke’s reps for comment.

If a royal reconciliation is on the cards, it’s likely that it would take place in September when Harry returns to the UK for the annual WellChild Awards.

His impending arrival on British soil has opened up the prospect of a potential meeting between the pair, which would mark their first in 18 months.

While a September meet-up between the father-son duo hasn’t been confirmed just yet, it may put the King in a tricky position as he’s set to welcome President Donald Trump at Windsor Castle for his upcoming state visit, slated for September 17.