This is a list of the individuals who were, at any given time, considered the next in line to succeed the British monarch to inherit the throne of the Kingdom of Great Britain (1707–1800), the United Kingdom of Great Britain and Ireland (1801–1922), and the United Kingdom of Great Britain and Northern Ireland (1922–present), should the incumbent monarch die or abdicate. Those who actually succeeded (at any future time) are shown in bold.
The list commences in 1707 following the Acts of Union, which joined the Kingdoms of England and Scotland (previously separate states, with separate legislatures but with the same monarch) into a single Kingdom of Great Britain. Anne became Queen of England, Scotland and Ireland on 8 March 1702 and Queen of Great Britain from 1707. The 1701 Act of Settlement established Electress Sophia of Hanover as successor to the English throne, and this was extended to Scotland through the Treaty of Union (Article II) and the Acts of Union.
Since the establishment of the British throne, there have been four heirs who did not become monarch but would have done so if they had only lived long enough: Sophia, Dowager Electress of Hanover, Frederick, Prince of Wales (son of George II), Frederick, Duke of York (brother of George IV), and Albert Victor, Duke of Clarence (son of the future Edward VII). There have been two younger brothers who were heir presumptive until the monarch had a child: Edward, Duke of York (brother of George III) and Ernest Augustus, Duke of Cumberland (uncle of Victoria). There has been one daughter of the monarch who was displaced as heir by her younger brother: Victoria, Princess Royal (daughter of Victoria).