Satirical cartoon of 1819 mocking the efforts of various members of the British royal family to produce an heir presumptive; at the time, King George III was dying and the heir apparent, later George IV, had no surviving legitimate children. The throne would pass to the heir presumptive, his younger brother William IV, in 1830; William had no surviving legitimate children either when he died in 1837, so Victoria, daughter of their brother Edward, became Queen. (In the cartoon, the woman in yellow is Princess Victoria of Saxe-Coburg-Saalfeld, depicted as heavily pregnant with the future Queen Victoria.)

An heir or heiress presumptive is the person entitled to inherit a throne, peerage, or other hereditary honour, but whose position can be displaced by a subsequent birth or recognition of a person with a better claim to the position in question. This is in contrast to an heir apparent, whose claim on the position cannot be displaced in this manner.

Overview

Depending on the laws controlling succession to the monarchy (or the rules of the peerage) in question, the heir presumptive might be:

  • the daughter of a monarch if males take preference over females and the monarch (as yet) has no son; or
  • or the senior member of a collateral line if the monarch is childless or if the monarch's direct descendants cannot inherit, either because: they are daughters, and females are completely barred from inheriting; the monarch's children are illegitimate; or some other legal disqualification exists, such as the descendant is descended from the monarch through a morganatic line, or the descendant refuses to or cannot adopt the religion that, to be monarch, the person is required to profess.

The subsequent birth of a legitimate child to the monarch may displace the heir presumptive by creating an heir apparent, or a more eligible heir presumptive. It is not assumed that the monarch and his or her consort are incapable of producing further children despite advanced age or infirmity. For example, on the day before Queen Elizabeth II ascended the British throne, her father GeorgeVIwas gravely ill and her mother was 51 years old, but Elizabeth was still the heir presumptive rather than heir apparent because of the remote possibility of her parents producing a son.

An heir presumptive's position may not be secure even after they ascend their throne, as a posthumous child, born after the death of his or her parent the late monarch, could have a superseding claim. Following the death of the childless King William IV of the United Kingdom in 1837, he was succeeded by his niece Victoria. Per the Regency Act 1830, however, Victoria's accession would be permanent only once it could be determined that William's widow Adelaide was not pregnant with a posthumous child. The possibility of such an event was even mentioned in Victoria's accession proclamation, even though Adelaide was 44 years old and had last been pregnant 17 years earlier. Had a child been born, he or she would have replaced Victoria on the throne. Such a situation occurred in Spain in 1885, when King Alfonso XII died and left behind his widow who was three months pregnant. His five-year-old daughter and heir presumptive, María de las Mercedes, was not declared queen because she would be displaced if a son was born; instead, there was a six-month interregnum until the birth of her brother Alfonso XIII, who assumed the throne as king immediately upon birth. Had the pregnancy been lost or resulted in another daughter, Mercedes would have become queen regnant and been retroactively recognized as having become queen upon the death of her father (which would have obviated the need for an interregnum, though only in hindsight).

Heir presumptive, like heir apparent, is not a title or position. Rather, it is a general term for a person who holds a certain place in the order of succession. In some monarchies, the heir apparent bears, ipso facto, a specific title and rank (e.g., in Denmark, the Netherlands, the United Kingdom where Prince of Wales is used to denote the heir apparent). This also is sometimes the case for noble titleholders (e.g., in Spain and the United Kingdom), but a mere heir presumptive does not bear—or is not traditionally given—that title. In other monarchies (e.g., in Monaco, Spain) the first in line to the throne always bears a specific title (i.e., "Hereditary Prince/Princess of Monaco", or Spain's "Prince/Princess of Asturias") by right, regardless of whether she or he is heir apparent or heir presumptive.

Simultaneous heirs presumptive

In Scots law and in the English and Welsh common law of inheritance, there is no seniority between sisters; where there is no son to inherit, any number of daughters share equally. Therefore, certain hereditary titles can have multiple simultaneous heirs presumptive. These are called, in Scotland for example, heirs portioner presumptive. Since most titles cannot be held by two persons simultaneously, two daughters (without a brother) who are to inherit in this way would do so as co-parceners; before they inherit, both are heirs presumptive. In these circumstances, the title would in fact be held in abeyance until one person represents the claim of both, or the claim is renounced by one or the other for herself and her heirs, or the abeyance is ended by the Crown. There are special procedures for handling doubtful or disputed cases.

Past heirs presumptive who did not inherit thrones

The list is limited to heirs presumptive who did not succeed due to death (heirs predeceasing their monarch parent), births of younger brothers, abolitions of monarchies, or changes in succession laws.