In one of our Wednesday discussions on Skype we were talking about the pros and cons of having a royal family, and a few of the participants weren't sure what the duties and powers of the British royal family are, so I've cobbled together this explanation, which may inform, or confuse you. The monarchy of the United Kingdom (commonly referred to as the British monarchy) is the constitutional monarchy of the United Kingdom and its overseas territories.
A constitutional monarchy is a form of government in which a monarch acts as head of state within the parameters of a constitution. This form of government differs from absolute monarchy in that an absolute monarch serves as the sole source of political power in the state and is not legally bound by any constitution. Yes, this means that England does not have a written constitution, in fact it's a bit of a political hot potato.
The present monarch of the United Kingdom, Queen Elizabeth II, has reigned since 6 February 1952. She and her immediate family undertake various official, ceremonial and representational duties. As a constitutional monarch, the Queen is limited to non-partisan functions such as bestowing honours, dissolving Parliament and appointing the Prime Minister. Though the ultimate executive authority over the government of the United Kingdom is still by and through the monarch's royal prerogative, in practice these powers are only used according to certain laws and strictures. Today the monarchy in Britain is politically neutral and by convention the role is largely ceremonial, that said, no person may accept significant public office without swearing an oath of allegiance to the Queen.
The British monarchy traces its origins from the Kings of the Angles and the early Scottish Kings. By the year 1000, the kingdoms of England and Scotland had developed from the petty kingdoms of early medieval Britain. The last Anglo-Saxon monarch (Harold II) was defeated and killed in the Norman invasion of 1066 and the English monarchy passed to the Norman conquerors. In the thirteenth century, the principality of Wales was absorbed by England, and the Magna Carta began the process of reducing the political powers of the monarch.
The Act of Settlement 1701, which is still in force, excluded Roman Catholics, or those married to Catholics, from succession to the English throne. In 1707, the kingdoms of England and Scotland were merged to create the Kingdom of Great Britain and, in 1801, the Kingdom of Ireland joined to create the United Kingdom of Great Britain and Ireland. The British monarch became nominal head of the vast British Empire, which covered a quarter of the world's surface at its greatest extent in 1921.
In the 1920s, five sixths of Ireland seceded from the Union as the Irish Free State, and the Balfour Declaration recognised the evolution of the dominions of the empire into separate, self-governing countries within a Commonwealth of Nations. After the Second World War, the vast majority of British colonies and territories became independent, effectively bringing the empire to an end. George VI and his successor, Elizabeth II, adopted the title Head of the Commonwealth as a symbol of the free association of its independent member states.
The Commonwealth includes both republics and monarchies. At present, fifteen other Commonwealth countries share with the United Kingdom the same person as their monarch. The terms British monarchy and British monarch are frequently still employed in reference to the person and institution shared amongst all sixteen of the Commonwealth realms, and to the distinct monarchies within each of these independent countries, often at variance with the different, specific, and official national titles and styles for each jurisdiction.
Queen Elizabeth II's full style and title is "Elizabeth the Second, by the Grace of God, of the United Kingdom of Great Britain and Northern Ireland and of Her other Realms and Territories Queen, Head of the Commonwealth, Defender of the Faith". The title "Head of the Commonwealth" is held by the Queen personally, and is not vested in the British Crown. Pope Leo X first granted the title "Defender of the Faith" to King Henry VIII in 1521, rewarding him for his support of the Papacy during the early years of the Protestant Reformation, particularly for his book the Defence of the Seven Sacraments, but after Henry broke from the Roman Church, Pope Paul III revoked the grant, however Parliament passed a law authorising its continued use.
The Queen is known as "Her Majesty", and a king would be known as "His Majesty". The form "Britannic Majesty" appears in international treaties and on passports to differentiate the British monarch from foreign rulers. The monarch chooses his or her regnal name, not necessarily his or her first name—King George VI, King Edward VII and Queen Victoria did not use their first names. In fact, if only one monarch has used a particular name, no ordinal is used; for example, Queen Victoria is not known as "Victoria I", and ordinals are not used for English monarchs who reigned before the Norman conquest of England. The question of whether numbering for British monarchs is based on previous English or Scottish monarchs was raised in 1953 when Scottish nationalists challenged the Queen's use of "Elizabeth II", on the grounds that there had never been a "Queen Elizabeth I" in Scotland. In MacCormick v. Lord Advocate, the Scottish Court of Session ruled against the plaintiffs, finding that the Queen's title was a matter of her own choice and prerogative. The Home Secretary told the House of Commons that monarchs since the Acts of Union had consistently used the higher of the English and Scottish ordinals, which in the applicable four cases has been the English ordinal. The Prime Minister confirmed this practice, but noted that "neither The Queen nor her advisers could seek to bind their successors". Future monarchs will apply this policy.
In the constitutional writer Walter Bagehot's words: "the Sovereign has, under a constitutional monarchy, three rights—the right to be consulted, the right to encourage, the right to warn."