If the queen can no longer do her duties, either in the short or long-term, the Regency Acts of 1937 and 1953 would come into play, Express explains. In cases of short-term illness, the sovereign is able to appoint someone to carry out her duties until she recovers. However, if she’s incapacitated, she’s unable to ask someone to stand in for her.
Incapacitated isn’t a term used lightly. In order for the queen to be deemed incapacitated, there must first be medical evidence. She must be judged “by reason of infirmity of mind or body incapable for the time being of performing the royal functions” by any three of her consorts, per Heraldica. Express explains it would be the next in line to the throne, Prince Charles, who would become regent. This doesn’t mean he would take over as king, but he would perform the duties of the sovereign until the queen’s health situation changes.
The Duke of Edinburgh was one of the consorts able to determine if the queen was incapacitated. However, since the death of Prince Philip, the determination is now up to Lord Chancellor Dominic Raab, House of Commons Speaker Lindsay Hoyle, the Lord Chief Justice, or the Master of Rolls, per Oh! My Mag. For now we wait and see what happens next.
