Prince Harry is once again taking aim at Kate Middleton over her treatment of Meghan Markle.

For years now, he’s been demanding an apology. “I am patiently waiting for accountability,” Prince Harry said upon the release of his scathing memoir, Spare, three years after he and wife Meghan Markle felt they had no choice but to leave the royal fold in 2020.

He went on to pointedly call out one unnamed family member: “You know what you did, and I know why you did it. And you’ve been caught out, so just come clean.”

It sounded like he was addressing his father, King Charles. But a source tells In Touch that Harry’s words were actually directed toward his brother’s wife, Kate Middleton.

“They used to be incredibly close, but Harry feels Kate betrayed him by shunning his wife,” the source says. The Sussexes retaliated by painting their sister-in-law in an unflattering light, not only in interviews and Spare, but by unofficially cooperating with the authors of Finding Freedom, Omid Scobie and Carolyn Durand.

The book is a deeply sympathetic account of Megxit. Now, Endgame, a new book also by Scobie, includes more criticism of the family — and Kate.

“Meghan admitted to helping him with the last book, so insiders suspect Harry secretly cooperated with the new one as well,” says the source. “He wants revenge.”

Finding Freedom first detailed how Harry’s once-close relationship with Kate soured. Scobie and his coauthor revealed Harry’s disappointment that Kate, 41, was “extremely guarded” around Meghan, 42, and described the women’s discord as “an offshoot of the real issue at hand: the conflict between Harry and the institution.”

In a bombshell 2021 interview, the Sussexes further alleged that Kate made Meghan cry, but The Firm chose to protect Kate’s reputation, not Meghan’s.

Harry, 39, then doubled down on Kate’s behavior in Spare, recounting incidents where the duchesses clashed over cultural differences — from sharing lip gloss to discussing pregnancy hormones — and even suggesting Kate felt threatened by his wife’s popularity.

Kate and William are bracing for worse with Endgame. The book promises to “pull back the curtain” on the royals, and William, 41, is described as the “power-hungry heir to the throne.” Kate “expects to be villainized as well,” says the source, noting that Scobie recently testified in Harry’s phone-hacking lawsuit against U.K. newspaper publishers.

“They both claim they’ve never met, but that doesn’t mean Harry couldn’t feed him information through other sources, like Meghan did by authorizing her friends to provide information for Finding Freedom.” And Harry, who’s described Kate as “the sister I’d never had and always wanted,” knows intimate details about her, adds the source, “that Kate definitely wouldn’t want to come out.”

Of course, the same goes for Harry. “Kate sees these tell-alls as a declaration of war,” says the source, “and she’s made it clear that there are two sides to the story.” It was Kate who helped craft the palace’s statement in response to Harry and Meghan’s interview, adding the line “some recollections may vary” to toughen it up, according to 2022’s Courtiers: The Hidden Power Behind the Crown.

And it’s Kate who has insisted William continue to ostracize his brother. “William is willing to extend an olive branch for the sake of the family, but Kate has drawn a hard line in the sand,” says the source.

“Forget about apologizing — she’ll never forgive Meghan and Harry. And if they push her too far, they’ll regret it.”

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