Revenue stamps of the United Kingdom
When Ireland was partitioned into Northern Ireland and Southern Ireland in 1921, separate revenue stamps were issued for both entities. Southern Ireland stamps saw little use since that political entity was quickly superseded by the Provisional Government of Ireland and later the Irish Free State (both of which applied overprints on various British and Irish revenue stamps). However, Northern Ireland continued to use separate revenue stamps until the 1980s. Northern Irish revenues include Civil Service, Dog Licence, Excise and National Insurance stamps, among many others.
Partition of Ireland
In May 1949 the Taoiseach John A. Costello introduced a motion in the Dáil strongly against the terms of the UK's "Ireland Act 1949" that confirmed partition for as long as a majority of the electorate in Northern Ireland wanted it, styled in Dublin as the "Unionist Veto". This was a change from his position supporting the Boundary Commission back in 1925, when he was a legal adviser to the Irish government. A possible cause was that his coalition government was supported by the strongly republican Clann na Poblachta. From this point on all the political parties in the Republic were formally in favour of ending partition regardless of the opinion of the electorate in Northern Ireland.