England and Wales
England and Wales are two separate countries within the United Kingdom. However, for certain administrative purposes they are treated as a single entity England and Wales. One such purpose concerns most legislation, as the two countries generally share the same laws. Other countries within the United Kingdom are Scotland and Northern Ireland, and the applicable laws within these countries often very different from that of England and Wales.
From the 1536 Act of Union until 1955, Wales was treated as part of England, so this formula was not necessary.