This postcard shows the centre of the Union Flag, the official flag of the UK. Geography Cat received it from his human assistants who posted it to him from London. Notice how it is incorrect if flown up-side down:
Great Britain and the United Kingdom are not exactly the same place, although not everyone can tell the difference.
The British Isles is a geographical term referring to the group of islands off the north east coast of Europe, including the large island of Great Britain, the island of Ireland and many smaller islands.
The island of Ireland is divided politically into two countries: Northern Ireland and the Republic of Ireland:
Meanwhile the island of Great Britain consists of England, Scotland and Wales:
Therefore Great Britain is Wales, Scotland and England only. The United Kingdom is the correct term for the political nation which consists of Northern Ireland, Wales, Scotland and England.
Geography Cat identifies as English, British and European, and he loves the whole world.