Should King Charles find himself unable to carry out his royal obligations for a limited time, he can appoint two or more individuals known as 'Counsellors of State' to serve on his behalf. This group is empowered to conduct a majority of the sovereign's official tasks, such as participating in privy council meetings, signing everyday documents, and receiving new ambassadors' credentials.

However, certain essential constitutional responsibilities are not permitted to be delegated. These include matters related to the Commonwealth, the dissolution of Parliament unless explicitly instructed by King Charles, creating peerages, and selecting a new Prime Minister. According to the Royal Family's official website, the Counsellors of State consist of the sovereign's spouse and the next four individuals in the line of succession above the age of 21.

Last year, concerns emerged when King Charles had to reduce his official activities due to treatment for an undisclosed cancer condition, sparking questions about who would manage his responsibilities during that time. Royal biographer Marlene Koenig noted that typically two Counsellors would be named for assistance. The likely candidates in this scenario would be Queen Camilla and Prince William, particularly in light of the fact that Prince Harry and Prince Andrew would not be called upon for these roles.

Koenig elaborated that Prince Harry is effectively removed from the list of Counsellors since he no longer resides in the UK after losing his lease for Frogmore Cottage, suggesting that Princess Eugenie would take his place. She remarked that adjustments made by King Charles regarding Counsellors in 2022 were aimed at circumventing the need to summon the Duke of Sussex or the Duke of York for duty. As of late 2024, Buckingham Palace confirmed that King Charles will continue his medical treatment after a challenging year battling illness.