FOR two weeks all eyes have been on the “difficult relationship” between royal wives Meghan and Kate.

But today the Sun can reveal the simmering tensions between brothers William and Harry are at the heart of the frostiness between the two couples.

It's not the girls, The Sun can reveal simmering tensions between William and Harry are at the heart of the frostiness between the two royal power couples Credit: Reuters

After we told exclusively how Harry and Meghan are moving to Windsor because they “don’t want to live next door to William and Kate” we can now unveil the “Fab Four’s” other issues, such as:

HARRY accusing Wills of trying to “wreck his relationship” with Meghan after he voiced concerns over her;

MEGHAN feeling rebuffed when she tried to befriend Kate;

RIVALRY between the brothers’ over palace appointments, and;

HARRY’S desire to protect his wife at all costs after not being able to do so for Princess Diana.

The frostiness between Kate and Meghan is clearly visible Credit: Getty - Contributor

From being young boys united in grief to building Britain’s modern monarchy together, the brothers could not have been closer.

Until now.

For insiders say it is problems between them, dating back to when Meghan, 37, appeared on the scene, that are fuelling the fallings-out.

And Harry’s over-protectiveness of his wife — and refusal to see reason — is the main cause of the chasm.

As one courtier told me: “It’s my opinion that Harry feels he couldn’t protect his mother, so he’s going all out to protect his wife.

“This is his way of atoning.

Royal insiders say it is problems between the princes, dating back to when Meghan, 37, appeared on the scene, that are fuelling the fallings-out Credit: Getty - Contributor

“He will brook absolutely no criticism of Meghan — and he is so sensitive he often sees criticism or negativity where there isn’t any.”

Of course, the brothers have locked horns before. William, 36, was said to be furious with Harry, 34, for getting caught on camera stripping in a Las Vegas hotel room six years ago.

And their teasing about everything from who’s the most bald to the better soldier has always been rife.

But they always turned to each other when times were tough — the only people who could truly understand their lives.

The first hint of friction came after William was introduced to Meghan, 37, when she was staying at Kensington Palace.

Harry has a strong desire to protect his wife at all costs after not being able to do so for Princess Diana Credit: Getty - Contributor

Once she’d returned home to Canada, Wills sat Harry down for a chat — meant as brotherly advice.

He knew Harry was already head-over-heels for the US star but wanted him to take it slowly.

A well-placed source said: “William told his brother they knew nothing about her background, her intentions, what she was really like.

“He just wanted to stress that becoming part of the Royal Family is a massive undertaking and the pressure and scrutiny is unrelenting. Was Meghan the right one?”

Harry and Meghan will move to Frogmore Cottage on the Windsor estate

The chat did not go down well.

“Harry went mental,” said the friend. “He accused his brother of trying to finish his romance before it had begun. The brothers’ relationship has not really recovered.”

The Sun understands other senior members of the family also “had concerns” and voiced them to Harry.

As one courtier cautiously volunteered: “A lot of people in the family objected. Who really knows what the concerns were? Was it Meghan’s background? Her father and dreadful half-sister? Because she was an outspoken American? Divorced?

“Harry stood up for Meghan very forcibly. He really loves her.”

Meghan also faced some opposition from the Middleton family, who didn’t want to invite her to Pippa’s wedding last May. They feared Meghan’s first public appearance with Prince Harry would overshadow the bride’s big day.

Meghan's father and other family 'dreadful' members are said to be behind some of the problems between Harry and William Credit: The Mega Agency

Eventually she was asked but chose only to go to the evening do.

So it was no surprise that when she moved to London last November — and her engagement to Harry was announced — she was desperate to make things work.

She hoped that in Kate, another “outsider” who had navigated the choppy waters with aplomb, she would find a natural best friend.

But Kate, 36, was recovering from terrible morning sickness in her pregnancy with Prince Louis and was busy with George, now five, and Charlotte, three.

Appearing on stage together, the Fab Four were asked if they ever had 'disagreements' where Meghan looked down, Kate fiddled with her hair and they left it to William, who answered with a very direct: 'Oh yes' Credit: Getty Images - Getty

A royal source said: “Meghan hoped Kate would show her the ropes. But, equally understandably, Kate was busy. She didn’t have as much time for her as Meghan would have liked. They were at very different places in their lives.

“Meghan felt quite let down. She had really tried but felt rebuffed, and so just stopped trying.”

Harry did not take this lightly and spoke to William about making Meghan feel welcome. William, of course, took his wife’s side — after all, she was following his lead.

In February, the Fab Four appeared on stage together for the first time to talk about their Royal Foundation charitable work.

Kate Middleton says she's very excited for Meghan and Harry's baby

Host Tina Daheley asked them: “Working together as a family, do you ever have disagreements about things?” Cue nervous laughter.

Meghan looked down, Kate fiddled with her hair and they left it to William, who answered with a very direct: “Oh yes.”

Harry then joked that there are so many clashes that “they come so thick and fast.” When asked if they’d been “resolved”, Wills jokingly replied: “We don’t know!” Could he have been thinking about Harry’s new role as a youth ambassador for the Commonwealth? Wills’ nose was reportedly put out of joint when the Queen gave the plum job to his brother instead of him.

Afterwards William had to be cajoled into doing anything for the Commonwealth, say courtiers.

Even Charles, who dotes on Meghan, asked a senior member of his staff to intervene in the feud Credit: Getty Images - Getty

But aides point out that if he’d wanted to veto Harry’s appointment, he could have done so. However, the tension didn’t help matters, coming as it did before May’s Royal Wedding.

Meghan’s father Thomas Markle was about to pull out of walking his daughter down the aisle after it was revealed he had posed for paparazzi pictures. Calm but collected, Meghan decided her team should say nothing publicly and cut him off.

However, William — having lost his mum — couldn’t understand ignoring a parent, whatever they’d done. He thought Meghan was making a mistake.

Even Charles, who dotes on Meghan, asked a senior member of his staff to intervene. But the policy stands and The Sun understands she has still not spoken to Thomas.

William infuriated Harry by saying they didn’t know enough about Meghan, insiders claim Credit: Getty - Contributor

Meghan is said to be far less intimidated by the royals than might be supposed. At a recent gathering of senior family members, including Meghan, one well-placed aide remarked: “All their IQs put together would not equal hers.”

She and Harry have started spending less time at Kensington Palace after taking possession of a Cotswold farmhouse in the spring.

The bolthole is used to entertain friends like Priyanka Chopra and Nick Jonas — now her husband — Serena Williams and George and Amal Clooney.

William and Kate also swerved a board meeting oft he Royal Foundation this week, leaving Harry and Meg to go alone.

They also missed the Christmas Party, with one insider saying: "it 'was a shame' they didn't attend."

Royal aides are said to be telling secrets of the rows between the the young royals Credit: Getty - Contributor

The source added: "Not only were Harry and Meghan there, but they went to the staff Christmas party afterwards.

"It was a very jolly affair. It's a shame that William and Catherine did not turn up.'"

Then Wills and Kate turned down an invite to the Castle of Mey with Harry, Meghan and Charles in June. And while the Cambridges holidayed with Zara and Mike Tindall, Peter and Autumn Phillips and their kids at Balmoral in August, Harry and Meghan were absent.

Next year the brothers are splitting their household, with staff choosing which prince to work for.

As the Sun revealed, Harry and Meghan will move to Frogmore Cottage on the Windsor estate.

As they prepare to become parents in the spring, perhaps Harry feels it’s time to spread his wings.

Admittedly things remain civil between the couples — and only this week Harry and Wills worked out their diaries together for next year.

But for these two brothers-in-arms, the bonds are creaking.

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