|Autonomous region of the United Kingdom|
|-||Lower house||House of Commons|
|-||Establishment||3 May 1921|
|-||Anglo-Irish Treaty||6 December 1922|
|a. A Council of Ireland was also envisaged with "a view to the eventual establishment of a Parliament for the whole of Ireland".|
Southern Ireland was a short-lived autonomous region of the United Kingdom, proclaimed on 3 May 1921 and formally dissolved on 6 December 1922. It was never effectively established.
Southern Ireland was established under the Government of Ireland Act 1920 together with its sister region, Northern Ireland. It was envisaged that Southern Ireland would have the following institutions:
It was also envisaged that Southern Ireland would share the following institutions with Northern Ireland:
The Parliament, although legally established, never functioned (for example, it never passed an Act). The House of Commons of Southern Ireland met just once with only four members present. No Government of Southern Ireland was ever established either. The Council of Ireland was to be established "with a view to the eventual establishment of a Parliament for the whole of Ireland", but it never came into being. The notable exception to the failure of the institutions of Southern Ireland was its courts, all of which functioned.
The Government of Ireland Act, also known as the Fourth Home Rule Act, was intended to provide a solution to the problem that had bedevilled Irish politics since the 1880s, namely the conflicting demands of Irish unionists and nationalists. Nationalists wanted a form of home rule, believing that Ireland was poorly served by the Government in Westminster and its Irish Executive in Dublin Castle. Unionists feared that a nationalist government in Dublin would discriminate against Protestants and would impose tariffs that would unduly hit the north-eastern counties of Ireland (these counties all being located within the province of Ulster), which were not only predominantly Protestant but also the only industrial area on an island whose economy was largely agricultural. Unionists imported arms and assorted weapons from Germany and established the Ulster Volunteer Force (the UVF) to prevent Home Rule in Ulster. In response to this, nationalists also imported arms and set up the Irish Volunteers. Partition, which was introduced by the Government of Ireland Act, was intended as a temporary solution, allowing Northern Ireland and Southern Ireland to be governed separately as regions of the United Kingdom of Great Britain and Ireland. One of those most opposed to this partition settlement was the leader of Irish unionism, Dublin-born Sir Edward Carson, who felt that it was wrong to divide Ireland in two. He felt this would badly affect the position of southern and western unionists.
In reality, however, while Northern Ireland did become a functioning entity, with a parliament and government that existed until 1972, Southern Ireland never did. An Irish Republic had been proclaimed by the parliament known as Dáil Éireann, formed by Sinn Féin MPs elected from Ireland in the United Kingdom general election in 1918. The first general election to the House of Commons of Southern Ireland in 1921, and the simultaneous general election to the House of Commons of Northern Ireland, was used by Sinn Féin to produce a single extrajudicial parliament, the Second Dáil. In the Southern Ireland constituencies Sinn Féin won 124 of the 128 seats, all without contest, while in the contested elections in Northern Ireland constituencies it secured six of the 52 seats, another six going to non-Sinn Féin nationalists. (The other four Southern seats were won by Dublin Unionists, who along with the 40 Unionists elected in the North, declined to participate in the second Dáil.) When the new Parliament of Southern Ireland was called into session in June 1921, only the four Unionist members of the House of Commons of Southern Ireland, and a handful of appointed senators, turned up in the Royal College of Science in Dublin, where the meeting was scheduled to take place; most of the others convened elsewhere as the Dáil.
The Anglo-Irish Treaty was further ratified on the Irish side on 14 January 1922 by "a meeting summoned for the purpose [of approving the Treaty] of the members elected to sit in the House of Commons of Southern Ireland" The Treaty, in specifying a "meeting of members", did not say that the Treaty needed to be approved by the House of Commons of Southern Ireland as such. The difference is subtle but was fully grasped by those who entered the Treaty. Hence, when that "meeting" was convened, it was convened by Arthur Griffith in his capacity as "Chairman of the Irish Delegation of Plenipotentiaries" (who had signed the Treaty). Notably, it was not convened by Viscount FitzAlan, the Lord Lieutenant of Ireland, who, under the Government of Ireland Act 1920, was the office-holder with the entitlement to convene a meeting of the House of Commons of Southern Ireland.
The Provisional Government of Southern Ireland envisaged under the Treaty was constituted on 14 January 1922 at the above-mentioned meeting of members of the Parliament elected for constituencies in Southern Ireland. It took up office two days later when Michael Collins became Chairman of the Provisional Government. Collins took charge of Dublin Castle at a ceremony attended by Lord FitzAlan. The new Government was not an institution of Southern Ireland as envisaged under the Government of Ireland Act. Instead, it was a Government established under the Anglo-Irish Treaty, and was a necessary transitional entity before the establishment of the Irish Free State on 6 December 1922.
Southern Ireland was self-governing but was not a sovereign state. Its constitutional roots remained the Acts of Union, two complementary Acts, one passed by the Parliament of Great Britain, the other by the Parliament of Ireland.
On 27 May 1922 (some months before the establishment of the Irish Free State) Lord FitzAlan, as Lord Lieutenant of Ireland, in accordance with the Irish Free State (Agreement) Act 1922 formally dissolved the Parliament of Southern Ireland and by proclamation called "a Parliament to be known as and styled the Provisional Parliament". From that date, the Parliament of Southern Ireland itself ceased to exist. With the establishment of the Irish Free State on 6 December 1922 under the terms of the Treaty, Southern Ireland ceased to exist.