Just thinking about this logically, every single referendum result that has gone against the EU has either been a) ignored or b) put back to the people to 'think again'. I think we'd all agree that they couldn't simply ignore a leave vote because all hell would break loose. So what would the response of the EU be to potentially losing one of it's biggest net contributors, one of the biggest economies on the planet, and it's largest export market? Would it be a c'est la vie approach of well they've voted to leave so we respect the outcome, or do they enter in to serious negotiations to address the concerns of the Brits and accept that we don't see things the same way? I'd say past experience would suggest we'll be ask to think again, but this can't happen without major concessions and this time the British PM won't have to go around kissing the arse of the Polish president to get them, because he'll have a much stronger hand to play with the very real threat of Britain leaving the EU if he doesn't get what he wants.