What would happen if King Charles III abdicated?

Abdication in the case of a British royal monarch has been rare. Still, King Charles III's recent cancer diagnosis has stirred up questions regarding the sovereign's position as head of state.

The news comes weeks after Queen Margrethe II of Denmark step down from her role as the country's monarch. The 83-year-old abdicated after 52 years of service, becoming the first Danish monarch to do so in over 900 years. Juan Carlos I of Spain abdicated in 2014 amid controversies, handing power to his son King Felipe VI.

Read on for what we know about abdication, and what would happen if Charles were to take that step.

What happens if a British monarch becomes too sick to rule?

According to University College London, the Regency Act 1937 established procedures to determine whether a monarch's mental or physical illness has incapacitated them. It also lays out what should take place if a monarch is deemed unable to rule.

The Regency Act establishes a regent, or a person to rule in the place of a monarch. Royal functions are passed to the next in line to the throne. In the case of King Charles III, that would be Prince William.

Regency Act, a regency is established and the royal functions are transferred from the sovereign to the next in the line of succession, namely Prince William the Prince of Wales.

What happens when a royal abdicates?

Abdication is like resigning from your job before your contract is over. When a monarch abdicates, that means he or she has given up their office and power.

Britannica defines abdication as the “renouncing of office and of power before the end of the term for which it was assumed.”

Has a British monarch ever abdicated? Inside Edward VIII's legacy

The last time the world saw a British monarch abdicate from the throne was in December 1936, and the effects were monumental.

Edward VIII served as the British monarch for 325 days before he announced that he would step down from his role in order to be with the woman he loved, American socialite and divorcée Wallis Simpson.

Edward's abdication meant that he and any future children of his would be excluded from the British royal line of succession.

It also meant that the office and power of the British monarchy was turned over to his younger brother, who would become King George VI.

The domino effects of the abdication continued and suddenly made George's daughter —the future Queen Elizabeth — heir presumptive.

How long has King Charles III been king?

Charles became King Charles III upon the death of his mother, Queen Elizabeth II, on Sept. 8, 2022. That means over 500 days have passed between his ascension to the throne and the public announcement of his diagnosis.

Charles was officially coronated several months after his mother's death, on May 6, 2023.

How would King Charles's abdication impact the line of succession?

According to the royal family’s website, since the 17th century, both descent and Parliamentary statutes have determined who will be the next monarch of Great Britain and the Commonwealth.

Charles' newly announced cancer diagnosis means there's a renewed curiosity about who will succeed him on the throne.

Currently, the royal line has determined that his eldest son, Prince William, is first in the line of succession and his grandson, George Alexander Louis, second in line.

This article was originally published on TODAY.com