The Duchess of Sussex, Prince Archie and Princess Lilibet will not accompany the Duke of Sussex to London next week, it is understood.
The decision was made after a row broke out over security for the family, resulting in a request for police protection being denied.
No decision has been made on whether they will join Prince Harry for the rest of his five-day trip to the UK.
However, the disappointing outcome has crushed hope for a long-awaited reunion between King Charles and his grandchildren, who he has not seen in four years.
The King was last with his grandchildren in person in 2020 the late Queen Elizabeth II’s platinum jubilee celebrations in 2022.
Harry was “desperate” for his seven-year-old son, Archie, and five-year-old daughter, Lilibet, to see their grandfather, the Telegraph reported.
He is reported to have been directly liaising with his father, King Charles, on any plans to meet. It would be the first time the duke has seen his father in nine months after the two had tea at Clarence House in September.
Meghan was due to join her husband in Birmingham on Friday at an Invictus Games engagement and a visit to the Royal Hospital Chelsea in London. Their children were not expected to attend any public events.
Among the two-week plans, the family was expected to visit Althorp, the Spencer family estate and resting place of the Duke’s late mother, Diana, Princess of Wales.
It is not clear whether Harry will accept an invitation to stay at a royal residence, as had been expected.
It also comes as the High Court ruling on the Duke’s privacy claim against the publisher of the Daily Mail is set be handed on Tuesday.
The duke was waiting for a review by the Risk Management Board (RMB), part of the process by which the Executive Committee for the Protection of Royalty and Public Figures (Ravec) rules on his security requirements.
His level of protection was downgraded in 2020 when he stepped back from royal duties, and he has not been given any police protection since, unless engaging in official royal occasions.
He is in an ongoing legal battle with the Home Office over security arrangements for him and his family while in the UK.
When the duke lost a Court of Appeal challenge against the Home Office last year, he gave a BBC interview in which he expressed hopes of a reconciliation with his family, revealing Charles would not speak to him because of his security court case.
Harry added: “I can’t see a world in which I would be bringing my wife and children back to the UK at his point and the things that they’re going to miss is, well, everything you know.”
