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 The latter were withdrawn soon afterwards upon the establishment of the Provisional Government, but the former continued to issue revenue stamps until the late 20th century.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.
Privy Council of Northern Ireland
The Council was created in 1922 as a result of the division of Ireland into the Irish Free State and Northern Ireland. The latter remained part of the United Kingdom albeit with its own parliament. The previous Privy Council of Ireland was obsolete although never formally abolished in British law.