Prince William is reportedly taking extraordinary steps to find out whether private royal information is making its way back to his estranged brother Prince Harry.

The future king, 44, has allegedly become so suspicious of leaks inside royal circles that he is testing people around him by sharing slightly different versions of sensitive information and watching to see which details eventually surface elsewhere.

According to palace insiders, William has become especially protective of information involving his wife, Catherine, Princess of Wales, 44, and their three children following Harry and Meghan Markle’s recent return to Britain with Prince Archie, 7, and Princess Lilibet, 5.

The Sussexes’ return has once again placed Harry, 41, physically closer to William and King Charles III, 77, even as tensions between the royal brothers remain deeply unresolved.

One royal source claimed William has become “exceptionally cautious” about who receives private information.

The alleged strategy is simple: Give different people slightly different details and, if one version later appears outside the Palace, William may be able to identify where the leak came from.

The source stressed that William does not necessarily believe Harry is running some kind of secret intelligence operation inside the monarchy.

Instead, the concern is reportedly that Harry spent most of his life inside the royal system and still has longtime personal relationships with people connected to the Palace.

Those relationships, insiders say, could allow private information to travel through seemingly innocent conversations before eventually reaching Harry or others in his circle.

The result has allegedly been an increasingly tense atmosphere behind Palace doors.

William is said to be keeping an especially tight grip on information surrounding Kate, Prince George, 13, Princess Charlotte, 11, and Prince Louis, 8.

Another palace insider said Harry would likely find the idea that he has secret royal “spies” ridiculous.

Harry still knows people he grew up around, the source explained, and those friendships did not simply vanish when he and Meghan stepped away from royal duties.

But with trust between William and Harry at rock bottom, even normal conversations can apparently spark suspicion.

“William is testing the waters by trying to use disinformation to plug any leaks,” the source claimed, adding that concerns remain that Harry could still be receiving inside Palace information.

Harry and Meghan dramatically stepped away as senior working royals in 2020 after their proposed plan to combine royal responsibilities with greater financial independence failed to win approval.

The family feud only became more explosive afterward.

In 2021, Harry and Meghan sat down with Oprah Winfrey for a bombshell interview filled with allegations about their treatment inside the monarchy.

They later released the Netflix series Harry & Meghan, while Harry went even further in his bestselling memoir Spare.

The book contained deeply personal claims about William, including Harry’s allegation that the brothers became physically confrontational during an argument at Nottingham Cottage.

William has largely refused to publicly respond to the accusations.

Harry’s relationship with his father, however, appears to have shown signs of improvement in recent years, with Charles and Harry reportedly re-establishing contact.

During a trip to Ukraine, Harry insisted he still sees himself as permanently connected to the monarchy.

“I will always be part of the Royal Family,” he said, adding that he continues doing work he believes he was “born to do.”

That does not mean Harry and Meghan have returned to their old roles.

Despite being back in Britain, the Duke and Duchess of Sussex have not been restored as working royals.

Amid the renewed tension, Kate is reportedly trying to prevent William and Harry’s bitter feud from poisoning the rest of the royal household.

Sources describe the Princess of Wales as taking a more diplomatic position than her husband.

Kate reportedly understands why William is fiercely protective of their family’s privacy, especially after years of public allegations and personal revelations involving the monarchy.

But insiders claim she worries that turning Palace employees, friends and relatives into suspected “camps” could make an already ugly family divide even worse.

“Catherine’s instinct is one of diplomacy,” one source said.

She reportedly does not want people who have known both brothers for years to feel they must prove their loyalty to William by abandoning Harry.

From Kate’s perspective, insiders say, the feud between William and Harry has already caused enough damage.

Her preference is reportedly to lower tensions, prevent the wider royal family from becoming divided and leave open the possibility that the brothers could eventually repair their fractured relationship.

For now, however, William appears to be taking no chances when it comes to protecting his wife, children and the secrets surrounding Britain’s future king and queen.