News that Prince Harry is set to bring his family to Britain for the first time in four years has sent hopes rising of an emotional – and long-overdue – reunion between the King and his grandchildren Archie and Lilibet.Indeed, to facilitate any such meeting, the whole Sussex family have been offered accommodation at a royal residence when they visit next month for an event promoting Harry’s 2027 Invictus Games in Birmingham.But the prospect of Charles reconciling with his younger son may have had the unfortunate side- effect of souring his relationship with his elder, I can reveal.Royal insiders this weekend claimed that the King’s willingness to extend an olive branch to Harry has led to an increase in long-simmering tensions with William, who is in no mood to forgive his brother.‘The King’s relationship with William is not in a good place,’ one well-connected source told me. ‘They are at a very low ebb.’However those claims were last night vehemently denied by those close to both the King and William. One source close to the Prince of Wales insisted that his relationship with the King is ‘incredibly positive’ and ‘unchanged’.The Sussexes have been reluctant to bring their children from California to the UK since Harry’s automatic access to 24-hour police protection here was removed following ‘Megxit’ in January 2020.It means Charles has not seen Archie, seven, and Lilibet, five, since the late Queen Elizabeth’s Platinum Jubilee in June 2022 – even though they are sixth and seventh in line to the throne. Royal insiders this weekend claimed that the King’s willingness to extend an olive branch to Harry has led to an increase in long-simmering tensions with William News that Meghan is accompanying her husband on the visit has not gone down well with some royals Rumours of tension between the King and William have been fuelled by what some insiders claimed was a froideur during Trooping the Colour last weekend.The MoS understands that just a few hours before the event marking the King’s official birthday, William learned that Meghan would be coming to the UK with Harry.The Prince of Wales is said to believe his father is making a ‘misjudgment’ in making efforts to rebuild a relationship with Harry, sources say.In contrast, William shows no signs of wanting to forgive his brother for the damaging claims he made in his memoir Spare and in a bombshell Oprah Winfrey interview in which he accused an unnamed royal of racism.William has allegedly barred any mention of his brother in his presence, with insiders saying he remains unwilling to even contemplate a reconciliation.The siblings are believed not to have spoken since the late Queen’s funeral in 2022.Some sources said that Princess Catherine, who usually maintains a flawless smile at high-profile events, appeared visibly tense during last Saturday’s pageantry. Reports noted that her usual warmth and composure ‘faltered’ and she seemed reluctant to smile and wave for the cameras from her horse-drawn carriage. At the time, this was put down to her having to face a barrage of jeers from anti-monarchy protesters, but sources claim that was not the full story.One insider said: ‘Queen Camilla, King Charles, and the Princess of Wales were not outwardly warm together that day and the reason was not just the protesters. Relations were decidedly frosty backstage.’Another source said: ‘So much of what they do is performative. But there was little performance on display that day.’Some details of Harry’s UK trip are believed to have been brokered by Theo Rycroft, the King’s hugely influential deputy private secretary who has emerged as a key peacemaker between Charles and Harry.It is understood that while the King has offered Harry and his family accommodation in a royal residence next month, he has yet to receive a reply. On a previous visit, Harry rejected a similar offer to stay at Buckingham Palace.The Mail on Sunday was first told of Meghan’s plans to accompany her husband to London last Friday. By Saturday morning, Kensington Palace was also learning more detail about the Sussexes’ visit.While privately digesting the news, William and Catherine put on a brave face on Horse Guards Parade, where they were accompanied by their children, Prince George, 12, Princess, Charlotte, 11, and Prince Louis, eight.It is claimed that by the time the Prince and Princess of Wales attended Royal Ascot on Wednesday, the dust had settled enough for Catherine to curtsey for her father-in-law, and at one point appeared to extend an arm towards him. She was also seen enthusiastically laughing and joking with her husband during the day, although they left early at 5.50pm – almost an hour before the King and the rest of the Royal Family.