Revenue stamps of Northern Ireland
Upon the partition of Ireland in 1921, separate revenue stamps began to be issued for both Northern Ireland and Southern Ireland. The latter were withdrawn soon afterwards upon the establishment of the Provisional Government, but the former continued to issue revenue stamps until the late 20th century. The need for separate issues for Northern Ireland came about since taxes raised there were meant to remain in the country. Most Northern Irish revenue stamps were British key types with appropriate inscriptions, but there were a number of different issues as well.
Irish issue in British politics
The Anglo-Irish War was fought between the forces of the provisional government of the Irish Republic and Britain, between January 1919 and July 1921. The British tried repressive force but the IRA under Michael Collins used about 3,000 fighters in asymmetric warfare. Prime Minister David Lloyd George presided over the Government of Ireland Act 1920 which partitioned Ireland into Southern Ireland and Northern Ireland in May 1921 during the Anglo-Irish War. Lloyd George used the threat of a massive war to force the Collins and his Irish negotiators to agree to the peace treaty in December 1922. It created a largely autonomous dominion, the Irish Free State, to replace the (failed) Southern Ireland. Meanwhile Northern Ireland, or Ulster, (with home rule) remained part of the United Kingdom. The Dail majority supported Collins and the treaty, but De Valera, President of the Dail, rejected it. De Valera led a civil war in Ireland that failed. The treaty with Britain went into effect and Northern Ireland remained with the UK.