http://eur-lex.europa.eu/legal-content/EN/ALL/;jsessionid=y2...
> The United Kingdom of Great Britain and Northern Ireland shall participate in the following provisions of the Schengen acquis: (etc.)
EDIT: oh not all of Ireland is in UK. I honestly didn't know about "Republic of Ireland" being a standalone country
Edit - I realize that came off snarky - it was meant lightheartedly. In all seriousness, though -
Republic of Ireland - a soverign nation of 26 counties. Split from the UK nearly a century ago. There's some interesting (but very painful) history behind that.
Northern Ireland - 6 counties at the northeast of the island
Ireland - a geographical entity (the island itself)
Ireland (or Eire) - the official name of the Republic
Great Britain - the island with England, Scotland, and Wales. Often used to refer to the UK (but this isn't completely accurate, if we're being pedantic it's a geographical, not political, term, and there's still Northern Ireland).
United Kingdom - England, Scotland (for now), Wales, and Northern Ireland
It would make sense for me to make an error in there, but I think I've got that right. Hope it's helpful!
And I'll just take solace in this (apparently) Scottish Proverb:
"He who asks is a fool for a moment. He who doesn't is a fool forever"