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 Southern Ireland stamps saw little use since that political entity was quickly superseded by the Provisional Government of Ireland and later the Irish Free State (both of which applied overprints on various British and Irish revenue stamps).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.
History of Northern Ireland
The Troubles was a period of ethno-political conflict in Northern Ireland which spilled over at various times into England, the Republic of Ireland, and mainland Europe. The duration of the Troubles is conventionally dated from the late 1960s and considered by many to have ended with the Belfast "Good Friday" Agreement of 1998. Violence nonetheless continues on a sporadic basis.