Modern organised unionism emerged after William Ewart Gladstone's introduction in 1886 of the first of three Home Rule Bills in response to demands by the Irish Parliamentary Party.

In September 1904, the Conservative government of Arthur Balfour published proposals for limited devolution to Ireland which would not amount to home rule.

Many southern unionist politicians quickly became reconciled with the new Irish Free State, sitting in its Senate or joining its political parties, while in Northern Ireland the existence of a separate Ulster Unionist Party became entrenched as it took control of the new Government of Northern Ireland, established in 1921.

[13] Sir James Craig, who in 1927 was created Viscount Craigavon, led the government of Northern Ireland from its inception until his death in November 1940 and is buried with his wife by the east wing of Parliament Buildings at Stormont.

A backbench revolt in 1943 resulted in his resignation and replacement by Sir Basil Brooke (later Viscount Brookeborough), although Andrews was recognised as leader of the party until 1946.

During this time he was on more than one occasion called to meetings of the Grand Orange Lodge of Ireland to explain his actions, most notably following the 1947 Education Act which made the government responsible for the payment of National Insurance contributions of teachers in Catholic Church-controlled schools.

Ian Paisley called for Brookeborough's resignation in 1953 when he refused to sack Brian Maginess and Clarence Graham, who had given speeches supporting re-admitting Catholics to the UUP.

In the 1960s, identifying with the civil rights movement of Martin Luther King Jr. and encouraged by attempts at reform under O'Neill, various organisations campaigned for civil rights, calling for changes to the system for allocating public housing and the voting system for the local government franchise, which was restricted to (disproportionately Protestant) rate payers.

His resignation was probably caused by a speech of James Chichester-Clark who stated that he disagreed with the timing, but not the principle, of universal suffrage at local elections.

Faulkner reacted by resigning with his entire cabinet, and the British Government suspended, and eventually abolished, the Northern Ireland Parliament, replacing it with Direct Rule.

The liberal unionist group, the New Ulster Movement, which had advocated the policies of Terence O'Neill, left and formed the Alliance Party of Northern Ireland in April 1970, while the emergence of Ian Paisley's Protestant Unionist Party continued to draw off some working-class and more loyalist support.

The Sunningdale Agreement, which led to the formation of a power-sharing Executive under Ulster Unionist leader Brian Faulkner, ruptured the party.

In the 1973 elections to the Executive the party found itself divided, a division that did not formally end until January 1974 with the triumph of the anti-Sunningdale faction.

In 1972, in protest over the prorogation of the Parliament of Northern Ireland, the Westminster Ulster Unionist MPs withdrew from the alliance.

[19][20][21] The party remained affiliated to the National Union of Conservative and Unionist Associations, but in 1985, withdrew from it as well, in protest over the Anglo-Irish Agreement.

Under West's leadership, the party recruited Enoch Powell, who became Ulster Unionist MP for South Down in October 1974 after defecting from the Conservatives.

The separate United Ulster Unionist Party (UUUP) emerged from the remains of Vanguard but folded in the early 1980s, as did the UPNI.

Unusually for a unionist party, the UUP had a Catholic MLA in the Northern Ireland Assembly, Sir John Gorman until the 2003 election.

Trimble faced down Orange Order critics who tried to suspend him for his attendance at a Catholic funeral for a young boy killed by the Real IRA in the Omagh bombing.

Empey justified the link by stating that under the d'Hondt method for allocating ministers in the Assembly, the new group would take a seat in the Executive from Sinn Féin.

In July 2008, the UUP and Conservative Party announced that a joint working group had been established to examine closer ties.

[29][30][31] The UUP's sole remaining MP at the time, Sylvia Hermon, opposed the agreement, stating she would not be willing to stand under the UCUNF banner.

[35] The Dublin-based political magazine, the Phoenix, described Elliott as a "blast from the past" and said that his election signified "a significant shift to the right" by the UUP.

In the 2011 local elections it lost seats to the Alliance Party east of the Bann and was also overtaken by them on Belfast City Council.

[52][53][54][55][56] In October 2021, Newry and Mourne UUP councillor Harold McKee resigned from the party because of Beattie's promotion of 'liberal values'.

[65] Following the losses for the UUP in the 2023 local elections, Beattie said that unionism was always likely to "take a hit across the board" due to Sinn Féin's gains.

"[67] In January 2024, it was announced that Iraq veteran Tim Collins had joined the UUP and been selected as the party's prospective parliamentary candidate for the North Down constituency.

[68] In May 2024, Antrim and Newtownabbey Councillor, Paul Michael quit the party following the decision to replace Robin Swann with Mike Nesbitt as Health Minister.

Each constituency association and representative body elects a number of delegates to the executive committee, which governs many areas of party administration such as membership and candidate selection.

[citation needed] The UUP maintained a formal connection with the Orange Order from its foundation until 2005, and with the Apprentice Boys of Derry until 1975.