* OK, where are we?  
(1) I have presented sourced evidence from official government websites (mostly Foreign Ministries or equivalent) that according to the governments of the UK, France and Italy, the EU is a member. 
(2) I have prsented sourced evidence from individual G8 websites, created by respective governments, that the EU is a member.  Nowhere is there any official statement that the EU is not a member. Some people are arguing that when it says the EU joined the G8, the word join has some special meaning (and they must therefore accept that Canada is not a member becasue I have shown the sentence where it says that both Canada and the EU 'joined'). 
(3) I have pointed out that most of the official G8 websites are quoting from the same source, so the contentious phrasing recure. 
(4) Lucy-marie quotes the sentence "The European Union is represented at the G8 by the president of the European Commission and by the leader of the country that holds the EU presidency." Of course it is. This sentence in many sources follows on from the sentence that says that countries are represented by their Head of State/Government and is needed simply because the EU does not have a Head of State/Government. It doesn't mean anything else. 
(5) Lucy-marie further quotes "The EU does not take part in G8 political discussions". Of course it doesn't: it would be quite wrong for the President of the Commission to do this since the EU cannot have a single view on these issues, being an association of many countries (some of which are represented in the G8 anyway). 
(6) Nowhere is there a source saying that the EU is not a member. I know, you can't prove a negative, but more significantly THERE IS NO SOURCE to say that the EU has partial membership, or restricted access, or observer status or anything other than full membership. If such exists, it should have been presented by now!