Monarch of the United Kingdom

The monarch of the United Kingdom is the head of state of the United Kingdom and its overseas territories in the broader Commonwealth of Nations. While the monarchy maintains formal executive authority over the country, those powers are constrained by law, precedent, and custom. For example, while the monarch appoints the prime minister, custom dictates that the monarch must appoint someone who has the support of the House of Commons. Thus, the Prime Minister's tenure in office is set by democratic election rather than by the monarch's choice. Moreover, the Prime Minister holds most of the actual power when it comes to setting and executing domestic and foreign policy.

In addition, the monarch is the Supreme Governor of the Church of England. Again, as in the secular realm, the monarch's role is more ceremonial, and the Archbishop of Canterbury is the true spiritual leader.

The monarch reigns for life. Succession is hereditary, and is governed by male-preference cognatic primogeniture. In October, 2011, the governments of the various commonwealths began the process of implementing legislation to do away with the male preference. Efforts are also being made to do away with the ban on Catholic rulers.

OTL
There have been 12 monarchs of United Kingdom proper, although the monarchy traces its origins back to both the monarchies of the Angles and the ancient Scots kings. The Kingdom of Great Britain was formed by the Acts of Union on 1 May 1707 with the merger of the Kingdom of England and the Kingdom of Scotland, which had been in personal union under the House of Stuart since March 1603. On 1 January 1801 Great Britain merged with the Kingdom of Ireland to form the United Kingdom of Great Britain and Ireland. After most of Ireland left the union on 6 December 1922, its name was amended to the United Kingdom of Great Britain and Northern Ireland on 12 April 1927.

Southern Victory
The reign of Victoria saw Britain intervene in North America twice in a generation. In 1862, Britain recognised the independence of the Confederate States, and forced a mediation upon the United States, bringing the War of Secession to a close. In 1881, Britain participated in the Second Mexican War, attacking the USA on several fronts, and annexing a part of Maine into Canada when the conflict ended in 1882.

However, the UK's participation in the Great War (in the reign of George V) and the Second Great War (in the reign of Edward VIII) proved disastrous for the country, as Britain was defeated both times, and devastated with superbombs in the last one.

The Two Georges
In the mid-1760s, King George III met with an American delegation led by Colonel George Washington. From this meeting, an agreement on colonial self-rule within the British Empire averted a feared revolution of the colonies against Great Britain, and led to the foundation of the North American Union. A famous painting commemorated this event.

The Union continued as a proud part of the Empire, naming its capital after Queen-Empress Victoria. In 1995, a plot by a separatist insurrection was thwarted in the capital, and the life of the visiting King-Emperor Charles III was saved.

Literary comment
The monarchs in this timeline seem to have followed the same chronology as in OTL, up until the 1930s. The dates from Edward VIII onward are estimates based on the information provided by the text.

Other Monarchs
In addition to the above, George III is referenced as the reigning monarch for part of the Atlantis series.

In addition to the above, Victoria is referenced as the reigning monarch in "Gentlemen of the Shade" and part of the Atlantis series.

George V is referenced obliquely as the reigning monarch in the early chapters of Joe Steele.

Edward VIII is the reigning monarch when The War That Came Early begins. The initial POD did not affect his abdication, which is referenced a few times in the series.

George VI is referenced as the reigning monarch for much of Joe Steele, the Worldwar tetraology, and The War That Came Early.

Elizabeth II is referenced as the reigning monarch in both Colonization and "Hindsight".

Henry IX, apparently a fictional character, is the reigning monarch in In the Presence of Mine Enemies. His lineage is unknown. He gives his blessing to the British Union of Fascists' decision to elect its leaders democratically in 2010.

An unidentified king, reigning over Great Britain (or perhaps just England - the novel is a little vague about this point) in the late 21st Century, is referenced briefly in Curious Notions.

Historical Monarchs in Non-Monarchical Roles
Edward VII is referenced as the current Prince of Wales in The Guns of the South and "The Scarlet Band".