December 2020 marked one hundred years since the Government of Ireland Act 1920 (“the 1920 Act”) received Royal Assent. This partitioned the island of Ireland – part of the United Kingdom since 1801 – and created what is still known as “Northern Ireland”.
As the historian Ivan Gibbons has written, the 1920 Act was “the single most important piece of British legislation of the twentieth century relating to Ireland in that it established a new constitutional and political arrangement (devolved government and partition) which exists to this day”.
The focus of this paper are the constitutional aspects of the 1920 Act and the role of UK Parliament. It is not intended as a general history of Northern Ireland. The passage of the 1920 Act marked the beginning of a process rather than a single event. From 1921 until the introduction of Direct Rule in 1972, what many considered the “constitution of Northern Ireland” underwent significant changes. It was also contested, for the 1920 Act never achieved cross-community consent.
Yet a lot of Northern Ireland’s early history has slipped from public consciousness. Events since the onset of the “Troubles” in 1969 have been extensively documented by historians, journalists and political scientists, the period prior to that less so. As another historian, Graham Walker, has observed, Northern Ireland “serves as a reminder that devolution and constitutional change has a long, complex, and fascinating history, and did not just appear magically at the end of the twentieth century”.
Some features of the 1920 Act survive: the Royal Courts of Justice in Belfast; separate Consolidated and National Insurance Funds; a distinct Northern Ireland Civil Service; and a distinctive division of excepted/reserved/transferred powers. Others do not, chiefly the bicameral Parliament of Northern Ireland, its single-party Government and vice-regal Governor. The Northern Ireland Assembly and Executive established by the Belfast/Good Friday Agreement and the Northern Ireland Act 1998 represented a deliberate break with the institutions envisaged in 1920.
This paper is also the story of the United Kingdom as it is currently constituted, for the Northern Ireland border created by the 1920 Act has been central to constitutional debate from the Anglo-Irish Treaty of 1921 to the Brexit controversies of 2016-21. It too evolved. Originally intended as a boundary between two devolved parts of the UK, by the end of 1922 it instead separated two parts of the British Empire. Only in 1949, when the Republic of Ireland left the British Commonwealth, did it become an international boundary.
Northern Ireland marked its centenary during 2021. It is hoped this paper will help inform the debates arising from that significant anniversary.