Use UK rather than United Kingdom.
- Great Britain is England, Wales and Scotland.
- The UK is Great Britain and Northern Ireland.
Use Ireland to refer to both the country and the island.
Use the Republic of Ireland to distinguish between it and Northern Ireland.
Ireland is an island to the west of England.
The Republic of Ireland’s capital is Dublin, and the capital of Northern Ireland is Belfast.
South Wales is not a defined geographical area. Refer to it as “south Wales” unless it is used as part of a proper noun.
South Wales Police has been tackling bicycle crime across south Wales.
The ONS Geography Guide to Presenting Statistics PDF provides a full list of UK countries and regions (on page 5).