It will only underline the key political question for Britain: does the UK want to stay in the EU but in the outer circle, does it want to free itself from the EU's embrace or will it select to join a more integrated Europe?

BBC: Why Cameron is backing closer European integration

Goldman has to stay out ahead of its rivals in trying daring and innovative approaches that push the outer edge of the boundary between what is okay and what may not be.

FORBES: Magazine Article

But the next implication is that tighter integration of the eurozone countries would put Britain more clearly on the outer ring of a two-speed Europe - less integrated and showing every sign of wanting to stay there.

BBC: Britain pushes hard choices for Europe's hard core