Board Thread:Random RP/@comment-26295802-20170107185243/@comment-25597877-20170111141648

Also this

The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain,[note 8] is a sovereign country in western Europe. Lying off the north-western coast of the European mainland, it includes the island of Great Britain (the name of which is also loosely applied to the whole country)

So while it may not be the official name it is acceptable to refer to it as such. Especially considering that those of English decent are almost always referred to as British