Rebecca English, the Daily Mail’s royal editor, commented that the action “was considered to have crossed a line.”

A source told the publication, “A deeply private call between the King and his grandchildren and it ends up in a newspaper the next day. Really?”

This incident has heightened concerns about private conversations being made public, leading to a lack of trust in sharing important information with Harry. As a result, he was reportedly not informed about the King’s cancer diagnosis until just before it was revealed to the rest of the world.

It is believed that the pair likely had one of their final phone conversations on Prince Harry’s milestone 40th birthday, which the Duke celebrated in September. However, no details about this phone call have been disclosed to the public.

It is also presumed that Harry would have called his father on Thursday to mark the King’s 76th birthday. The last time they reportedly saw each other was in February when Harry traveled across the Atlantic after learning about the monarch’s cancer diagnosis.

Former royal butler Grant Harrold, who worked for the King during his time as the Prince of Wales from 2004 to 2011, has suggested that trust might be a barrier to Harry being fully welcomed back into the royal family. When asked if the Duke could return to royal life, Harrold told Express.co.uk: “I think the trust with the Royal Family is a big issue and I think in the back of their minds they are always going to worry.

“Never say never, time is a healer. I think it depends on what he does over the next couple of years if we can see him come back in. I’m sure his father would probably love to welcome him back with open arms, they’ve just got to be sure that what’s happened in the past few years is not going to happen again.”