Gathered for a celebration of the Queen’s 90th birthday, Kate was pictured walking alone ahead of the two sisters.
“Some say that this froideur, on what was supposed to be an idyllic occasion, a celebration of the Queen’s 90th birthday, is not new.”
The article pointed out that these tensions are “rooted in far more than mere sartorial competitiveness”, with resentment growing over what the York sisters see as Kate’s “preferential treatment” by the rest of the royals.
A royal insider said: “Despite being the only young ‘blood Princesses’ (in other words, born royal), Beatrice and Eugenie have been reduced to walk-on parts in Royal Family life.
“It particularly hurt when Kate did solo engagements with the Queen during the Diamond Jubilee. They felt snubbed.”
The news is in contrast to how the royal children grew up, as they were extremely close when they were children.
There was even a time when the future King played a cruel trick on his young cousins.
According to the UK's OK! Magazine, former royal chef Darren McGrady revealed that one year, William decided to make a Hickory Dickory Dock nursery rhyme themed chocolate egg.
"It had a clock on the top striking one and a sugared mouse peeking out of a mousehole," he told the UK publication.
"We sent it up to the nursery on the silver tray, but 15 minutes later the Footman brought it back.
"He said, 'Nanny asked me to return this. Prince William has just stood on a chair and bitten the mouse’s head off, frightening Beatrice and Eugenie.'"
But all was not lost, and the chef quickly got to work making another mouse.
He said: "We had to quickly make another mouse, pop it in the hole and send it back to the nursery.
"I think Nanny put the egg out of William’s reach to make sure it didn’t happen again."