Prince William has lost trust in his brother Harry, and is growing increasingly wary that any conversation between them will be leaked to the media. Royal experts believe that only their grandmother Queen Elizabeth II can "make him (Harry) see sense."

With just a week left until their reunion at the unveiling of a statue of their mother, Princess Diana, the Duke of Cambridge is getting more "cautious" of talking to his only sibling. "I don't think William trusts Harry anymore and he is always worried that anything he says will end up in the press in two or three days' time. That's what he is worried about, and he needs to be cautious of what he can actually say to him," Royal author Phil Dampier said on True Royalty TV's weekly programme "The Royal Beat."

Harry is returning to the UK for the memorial ceremony at Kensington Palace on July 1, which would have been Diana's 60th birthday. Vanity Fair's royal correspondent Katie Nicholl said the Queen is the one member of the royal family who can help her grandsons in resolving their differences when they get together next month.

"She is the only person who can talk to Harry in a certain way and make him see sense," Nicholl said.

Meanwhile, royal historian Robert Lacey recently claimed that William had worked with the Queen ahead of Prince Philip's funeral to ensure that he wasn't walking next to Harry when their grandfather's coffin was carried from Windsor Castle to St. George's Chapel.

In his book "Battle of Brothers" about William and Harry's feud, which is being serialised in The Times, Lacey wrote: "When it came to the funeral the following weekend, William and his grandmother worked out together how, in the prevailing circumstances, he could not possibly walk in harmony with Harry behind his grandfather's coffin in the way that he might have done in the past."

Their cousin Peter Philips, the son of Princess Anne and the monarch's eldest grandchild, had walked between William and Harry as they escorted the Prince Consort's coffin.

"The device of recruiting cousin Peter Phillips, Princess Anne's beefy son, to serve as a diplomatic buffer between the two brothers had been deployed before — two years earlier at the Easter Sunday service at Windsor in April 2019, after William and Harry had gone public with the news that they were splitting their combined households," Lacey pointed out.

William and Harry at Pippa Middleton wedding
Prince William, Duke of Cambridge and Prince Harry arrive for the wedding ceremony of Pippa Middleton to James Matthews at St Mark's Church on 20 May Arthur Edwards - WPA Pool/Getty Images