Tensions between Princes Harry and William are at the centre of ongoing difficulties between the two brothers and their royal wives, reports claim.
Despite being close over the years, the two are believed to have hit rocky ground since Harry began dating Meghan Markle.
According to The Sun, insiders close to the couples say Harry's over-protectiveness of his new wife has put strain on his relationship with his brother.
A courtier told the paper: "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."
William reportedly voiced concerns over Meghan, only for Harry to accuse him of attempting to "wreck" his relationship with the retired actress.
But difficulties between the two couples are believed to go even deeper, with Meghan reportedly left feeling rebuffed after trying to befriend the Duchess of Cambridge.
The Sun reported that the first sign of tension came when Harry introduced William to Meghan, during her first stay at Kensington Palace.
A source said: "William told his brother they knew nothing about her background, her intentions, what she was really like."
The friend said the chat did not go down well and Harry "went mental", accusing his brother of attempting "to finish his romance before it had begun". They added: "The brothers' relationship has not really recovered."
One courtier told the Sun that it wasn't just Wills, with "a lot of people in the family" also objecting to Harry's new romance.
But Harry is believed to have stood up for Meghan "very forcibly" – a sign that he "really loves her".
After Meghan moved to London in November last year and her engagement to Harry was announced, she reportedly approached Kate to seek friendship and advice from a fellow 'outsider'.
But Kate had her hands full, being pregnant with Prince Louis, busy looking after her children George and Charlotte, and recovering from a stretch of bad morning sickness. Rumours of a feud between the two wives have since surfaced.
Who really knows what the concerns were? Was it Meghan’s background?The Daily Express has reported that differences in Kate and Meghan's upbringings, and the effects family interactions have had on their contrasting personalities, might also be adding to tensions.
A psychologist told the paper: "Meghan's personality was one which absorbed her environmental and social influences, she was aware of the daily friction and conflict in her mum and dad's constant stressful relationship and fathers absence as he was working excessively long hours as a film director in LA.
"By contrast, Kate Middleton was born into the English middle classes and later was to become a legitimate member of aristocracy."
He added: "Her environmental influences were such that her parents had wealth charm and a good pedigree."
The two couples appeared on stage back in February to discuss their Royal Foundation charitable work, and when host Tina Daheley asked if they ever disagreed over anything, Meghan looked away and Kate fidgeted with her hair.
Wills answered "Oh yes" and Harry joked that the clashes "come so thick and fast", and when asked if they had since been resolved, William told the host "We don't know!"
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