But fast forward to today, and the warring siblings are embroiled in a bitter feud as they carve out separate lives on opposite sides of the Atlantic. The breaking point in their bond came after Harry married wife Meghan Markle – and their pair struggled to adapt to royal life.

And in the Sussexes’ controversial Netflix docuseries, Harry & Meghan, the couple take aim at William and recall a flashpoint that Harry claims left him furious and his wife in floods of tears. It came when Harry says he did not give his permission for a joint palace statement to be put out dismissing bullying claims – and says a wedge was driven between the pair.

Speaking over clips of the brothers playing in an old fire truck and newspaper headlines about the acrimony in their relationship in episode five, Harry said: “I mean, the saddest part of it was this wedge created between me and my brother so that he’s now on the institution’s side.

“And I get, part of that I get. I understand right? That’s his inheritance, so to some extent it’s already ingrained in him that part of his responsibility is the survivability and the continuation of this institution. That day, a story came out that part of the reason why Meghan and I were leaving was because William had bullied us out. And once I got in the car after the meeting, I was told about a joint statement that had been put out in my name and my brother’s name squashing the story about him bullying us out of the family.

“I couldn’t believe it. No one had asked me permission to put my name to a statement like that. And I rang M and I told her and she burst into floods of tears because within four hours they were happy to lie to protect my brother and yet for three years, they were never willing to tell the truth to protect us.”

Last week, Harry marked his 40th birthday and nobody could have quite predicted how his estranged royal relatives would publicly mark the day. But what played out was both King Charles and William taking to their official social media accounts to send on their regards. For the first time in three years, the Royal Family account shared a post on X that said simply: “Wishing The Duke of Sussex a very happy 40th birthday today!” The message was also accompanied by a picture of a smiling Harry and an emoji of a birthday cake.

Around an hour later, the same post was shared by the Prince and Princess of Waleses’ X account along with the message: “Wishing a Happy 40th Birthday to The Duke of Sussex!” Some will see the post as a surprise move given the unresolved tensions between the brothers, which has shown no sign of abating.

But according to royal biographer and editor-in-chief of Majesty Magazine Ingrid Seward, there was a big reason for the message. She told the Mirror : “King Charles would have celebrated his son’s 40th from a distance. Milestone birthdays are important to the royals. Whatever upsets Harry has caused would have been forgotten for the day.

“Even Prince William wished his brother Happy Birthday – even if it was through clenched teeth. He doesn’t trust him, but together with his family, he wished him the best on his milestone birthday.”