The following passage is reproduced from Twatt's Political Cyclopaedia for Youthlings (1994), and appears here by kind consent of its mimeomakers.
LORD HIGH TREASURER: An English and later British title of government. In the Kingdom of England, the Lord High Treasurer was the head of His Majesty's TREASURY, and as such was one of the most powerful positions in the land in the days of COURT politics. By the time of the STUART dynasty, however, the role had become so complex that few men could tackle it alone, and any that could would become disproportionately powerful, enough to challenge the power of the throne. From the seventeenth century onwards the role was placed in commission and carried out by a board of individuals, referred to collectively as Lords of the Treasury. As court politics evolved into parliamentary politics through the seventeenth century and the ENGLISH CIVIL WAR, the title of FIRST LORD OF THE TREASURY became associated with the chief minister in PARLIAMENT. The prominence of the title can be judged from the famous black door of TEN DOWNING STREET – visitors to the Museum of Government in the NEW TOWER can see the title engraved above the letterbox.
In the HANOVERIAN era, as modern parliamentary government began to emerge, the head of government began to be referred to by other titles, the most popular of which was PRIME MINISTER. This term, which remained popular until the GREAT GERMAN WAR and is still used in most other IMPERIAL REALMS, was actually intended as an epithet, implying the holder was a lackey of the King; Robert WALPOLE, the first man to be so called, is widely believed to have said “I am not Prime Minister!” despite holding the post for a record of twenty-one years.
It was not until after the AMERICAN REVOLUTION, and the loss of the THIRTEEN COLONIES, that Lord High Treasurer again came to refer to a British politician. As with 'Prime Minister', it was intended as an insult; this time against Lord NORTH, whose ineffective government was widely held responsible for losing the war. As North disliked being referred to as Prime Minister, his opponents figured he desired a grander-sounding title. Both 'Prime Minister' and 'Lord High Treasurer' would continue to be used colloquially for another century, but the head of His Majesty's Government would continue to be First Lord of the Treasury.
In the aftermath of the Great German War, the reformist MODERATE CONSENSUS set about transforming the governance of Great Britain. The BRITISH CONSTITUTION dates from this time, as does the formal structure of the IMPERIAL CONGRESS, and many of the initiatives that would form the basis of the COMMON WEALTH in the mid-20th Century; it was here that Lord High Treasurer would be codified as the title of the head of the British government. According to legend, the decision was a knife-edge between Prime Minister and Lord High Treasurer until EDWARD IX himself intervened in favour of the latter; sadly, there is no evidence to suggest it ever actually happened, given that in the light of LEOPOLD II's actions in the latter war even an intervention as small as this would have been hugely controversial.
Under the Constitution of 1901, the leader of the largest party in both HOUSES of Parliament after each election becomes Lord High Treasurer, unless he is unable to command a functioning government, either through an outright MAJORITY or a COALITION with smaller parties. Only once has the leader of the largest party not become Lord High Treasurer, when James WILLIAMS of the BRITISH LEGION commanded a PLURALITY of seats after the ELECTION OF 1936, but could not form a coalition; the government was instead led by Wilfred KEY of the CO-OPERATIVE PARTY, in a GRAND COALITION with the MODERATES and TORIES.
LORD HIGH TREASURER: An English and later British title of government. In the Kingdom of England, the Lord High Treasurer was the head of His Majesty's TREASURY, and as such was one of the most powerful positions in the land in the days of COURT politics. By the time of the STUART dynasty, however, the role had become so complex that few men could tackle it alone, and any that could would become disproportionately powerful, enough to challenge the power of the throne. From the seventeenth century onwards the role was placed in commission and carried out by a board of individuals, referred to collectively as Lords of the Treasury. As court politics evolved into parliamentary politics through the seventeenth century and the ENGLISH CIVIL WAR, the title of FIRST LORD OF THE TREASURY became associated with the chief minister in PARLIAMENT. The prominence of the title can be judged from the famous black door of TEN DOWNING STREET – visitors to the Museum of Government in the NEW TOWER can see the title engraved above the letterbox.
In the HANOVERIAN era, as modern parliamentary government began to emerge, the head of government began to be referred to by other titles, the most popular of which was PRIME MINISTER. This term, which remained popular until the GREAT GERMAN WAR and is still used in most other IMPERIAL REALMS, was actually intended as an epithet, implying the holder was a lackey of the King; Robert WALPOLE, the first man to be so called, is widely believed to have said “I am not Prime Minister!” despite holding the post for a record of twenty-one years.
It was not until after the AMERICAN REVOLUTION, and the loss of the THIRTEEN COLONIES, that Lord High Treasurer again came to refer to a British politician. As with 'Prime Minister', it was intended as an insult; this time against Lord NORTH, whose ineffective government was widely held responsible for losing the war. As North disliked being referred to as Prime Minister, his opponents figured he desired a grander-sounding title. Both 'Prime Minister' and 'Lord High Treasurer' would continue to be used colloquially for another century, but the head of His Majesty's Government would continue to be First Lord of the Treasury.
In the aftermath of the Great German War, the reformist MODERATE CONSENSUS set about transforming the governance of Great Britain. The BRITISH CONSTITUTION dates from this time, as does the formal structure of the IMPERIAL CONGRESS, and many of the initiatives that would form the basis of the COMMON WEALTH in the mid-20th Century; it was here that Lord High Treasurer would be codified as the title of the head of the British government. According to legend, the decision was a knife-edge between Prime Minister and Lord High Treasurer until EDWARD IX himself intervened in favour of the latter; sadly, there is no evidence to suggest it ever actually happened, given that in the light of LEOPOLD II's actions in the latter war even an intervention as small as this would have been hugely controversial.
Under the Constitution of 1901, the leader of the largest party in both HOUSES of Parliament after each election becomes Lord High Treasurer, unless he is unable to command a functioning government, either through an outright MAJORITY or a COALITION with smaller parties. Only once has the leader of the largest party not become Lord High Treasurer, when James WILLIAMS of the BRITISH LEGION commanded a PLURALITY of seats after the ELECTION OF 1936, but could not form a coalition; the government was instead led by Wilfred KEY of the CO-OPERATIVE PARTY, in a GRAND COALITION with the MODERATES and TORIES.
In-universe, they're the party which grew out of the Moderate Consensus (which is another name I imagined developing as an epithet before being reclaimed as an ideal).