Ulster Unionist Party in the context of "Irish Unionist Alliance"

General elections took place in Ireland on 24 May 1921 to elect members of the House of Commons of Northern Ireland and the House of Commons of Southern Ireland. These legislatures had been established by the Government of Ireland Act 1920, which granted Home Rule to a partitioned Ireland within the United Kingdom.

The Ulster Unionist Party (UUP) won a landslide majority in Northern Ireland. In the area designated as Southern Ireland, Sinn Féin candidates were elected unopposed in 124 of the 128 seats.

The prime minister of Northern Ireland was the head of the Government of Northern Ireland between 1921 and 1972. No such office was provided for in the Government of Ireland Act 1920; however, the Lord Lieutenant of Ireland, as with governors-general in other Westminster systems such as in Canada, chose to appoint someone to head the executive even though no such post existed in statute law. The office-holder assumed the title prime minister to draw parallels with the prime minister of the United Kingdom. On the advice of the new prime minister, the lord lieutenant then created the Department of the Prime Minister. The office of Prime Minister of Northern Ireland was suspended in 1972 and then abolished in 1973, along with the contemporary government, when direct rule of Northern Ireland was transferred to London.

The Government of Ireland Act provided for the appointment of the executive committee of the Privy Council of Northern Ireland by the governor. No parliamentary vote was required. Nor, theoretically, was the executive committee and its prime minister responsible to the House of Commons of Northern Ireland. In reality the governor chose the leader of the party with a majority in the House to form a government. On each occasion this was the leader of the Ulster Unionist Party; such was the UUP's electoral dominance using both a simple plurality and for the first two elections, a proportional electoral system. All prime ministers of Northern Ireland were members of the Orange Order.

John Enoch Powell (16 June 1912 – 8 February 1998) was a British politician, scholar and writer. He was Member of Parliament (MP) for Wolverhampton South West for the Conservative Party from 1950 to February 1974 and the MP for South Down for the Ulster Unionist Party (UUP) from October 1974 to 1987. He was Minister of Health from 1960 to 1963 in the second Macmillan ministry and was Shadow Secretary of State for Defence from 1965 to 1968 in the Shadow Cabinet of Edward Heath.

Before entering politics, Powell was a classical scholar; in 1937 he was appointed Professor of Greek at the University of Sydney, aged only 25. He served in the British Army during the Second World War, reaching the rank of brigadier. He wrote both poetry and books on classical and political subjects. He is remembered particularly for his views on immigration and demographic change. In 1968 Powell attracted attention nationwide for his "Rivers of Blood" speech, in which he criticised immigration to Britain, especially the rapid influx from the Commonwealth of Nations (former colonies of the British Empire) in the post-war era. He opposed the Race Relations Bill, a major anti-discrimination bill which ultimately became law. His speech was criticised by some of his own party members and The Times as racialist. Heath, who was then the leader of the Conservative Party and the leader of the Opposition, dismissed Powell from the Shadow Cabinet the day after the speech. In the aftermath several polls suggested that between 67 and 82 per cent of the British population agreed with Powell.

The 1970 United Kingdom general election was held on Thursday 18 June 1970. It resulted in a surprise victory for the Conservative Party under leader Edward Heath, which defeated the governing Labour Party under Prime Minister Harold Wilson. The Liberal Party, under its new leader Jeremy Thorpe, lost half its seats. The Conservatives, including the Ulster Unionist Party (UUP), secured a majority of 30 seats. This general election was the first in which people could vote from the age of 18, after passage of the Representation of the People Act the previous year, and the first UK election in which party affiliations of candidates were put on the ballots.

Most opinion polls prior to the election indicated a comfortable Labour victory, and put Labour up to 12.4% ahead of the Conservatives. On election day, however, a late swing gave the Conservatives a 3.4% lead and ended almost six years of Labour government, although Wilson remained leader of the Labour Party in opposition. Writing in the aftermath of the election, the political scientist Richard Rose described the Conservative victory as "surprising" and noted a significant shift in votes between the two main parties. The Times journalist George Clark wrote that the election would be "remembered as the occasion when the people of the United Kingdom hurled the findings of the opinion polls back into the faces of the pollsters".