When to use イギリス and 英国?


Does イギリス and 英国 mean the same thing? Looking at
[jisho](http://beta.jisho.org/search/united%20kingdom) it seems they do.

I know 国 mean country and I think 英 means English. So together it means
English Country I guess. イギリス is written in Katakana so it's probably a
foreign word but I can't recognise the English word it was derived from.
Perhaps it doesn't come from English.

Anyway in what situations would you use one over the other?

