oh and a bit of evidence as to why I think I'm right.
http://www.wordiq.com/definition/Great_Britain
and an extract from wikipedia
Use of the term Great Britain
"Great Britain" refers to the majority of the "United Kingdom of Great Britain and Northern Ireland" (UK). It refers to the largest island only, or to England, Scotland and Wales as a unit (though these three countries also include many smaller islands). It does not include Northern Ireland.[29]