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 Southern Ireland stamps saw little use since that political entity was quickly superseded by the Provisional Government of Ireland and later the Irish Free State (both of which applied overprints on various British and Irish revenue stamps).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.
United Ireland
The Northern Ireland Act 1998 supersedes previous similar legislative provisions. The Northern Ireland Constitution Act 1973 also provided that Northern Ireland remained part of the United Kingdom unless a majority voted otherwise in a referendum, while under the Ireland Act 1949 the consent of the Parliament of Northern Ireland was needed for a united Ireland. In 1985, the Anglo-Irish Agreement affirmed that any change in the status of Northern Ireland would only come about with the consent of a majority of the people of Northern Ireland.