The UK

Ask England.

as the queen,



and NORTHERN IRELAND FOR THE WIN :D

It probably has to do with it's history.

They each include different countries from the uk:
Great britain= England, Scotland and Wales
United Kingdom= England, Ireland, Scotland and Wales.
England is just England.

This is why there are different names as they aren't all the same thing. I know all this as I learnt about it in Geography plus I live in England so I know.

England is a country.

Great Britian is England and Wales. (I believe, not toooooo positive)

The United Kingdom is England, Wales, Scotland and Northern Ireland.

^^~

i have no idea

*Extreme facefuck*

England IS part of the United Kingdom, it's on the whole continent.
And if you want to know about the United Kingdoms history then ask the queen, she knows more about the country then any of us here do.