There are several good reasons why King Charles lets his beloved niece Zara Tindall break the rules all the time. For one, he clearly adores her big protocol-destroying bear hugs, which were on full display during a tender reunion at the Royal Windsor Horse Show recently.

Charles, 75, has also been working behind the scenes putting together plans to rebuild his dwindling ranks and wants to promote the mother-of-three to her rightful title of princess. And onlookers are convinced this is the moment he told her!

“He was thrilled to see her, and there was something he said that definitely made her pause for a moment,” says an eyewitness. “It would be amazing if he were to make her a princess. She’s like a surrogate daughter for him. He clearly worships her.”

It’s clear the King’s initial plans for a more streamlined monarchy have somewhat backfired, with the Princess of Wales convalescing and his own ailments restricting him, and bringing in someone like Zara will have a big impact.

“She’s an absolute powerhouse for the royals, even in her unofficial capacity,” says an insider. “Everyone loves her. She’s an incredible mum, has an amazing husband and she’s won silver at the Olympics. But more than that, Charles adores her and wants her on his team.”

Charles may have his work cut out for him after good sport Zara, who turns 43 this week, said on The Total Sport Podcast last December she had no regrets about her status. “I was obviously very lucky that my mother didn’t give us any titles so I really commend her on that,” she said. “We got to do it a bit our way.”

But now they’ve had their “normal” upbringing, Charles is not giving up.

“He wants to do this because it’s wrong that Zara and her brother Peter aren’t princess and prince,” says an insider.

“They would have automatically been afforded those titles had Anne been a boy. It doesn’t matter that Anne turned down the Queen’s offer to fix this when they were younger. If they’ve changed the laws of succession to include females, then Zara should automatically be a princess.

“She can turn it down, but Charles is hoping she won’t. He adores her – she’s the daughter he never had – and he respects and admires her as much as his sister.”