No, there is a third option that is looking increasingly credible: the UK could leave the EU altogether. Whatever the arguments for being in or out more generally, in financial terms that is almost certainly a win as things stand today, and it looks like any realistic outcome of the Euro problems will only strengthen the case.
I'm not sure about that, if the UK wants to continue trading with the EU from outside then they will be forced to pay for that privilege some way or another.
But the "Europe project" originally was about free trade. It worked pretty well for the most part, too: we managed with multilateral free trade agreements for years without things like legislative policy and currency getting centralised as well, and there are still alternative platforms for cooperation like the EFTA and EEA, which for example include some Scandinavian nations that are not part of the EU.
Given the UK's disproportionate strength, I don't see why it couldn't move to a similar relationship to what those Scandinavian nations have with Europe, being outside of the main EU and the Eurozone but still sharing common ground elsewhere. So until someone wiser about economics tells me otherwise, I think I stand by my previous position: whatever the pros and cons of being in the EU more generally, financially it's almost certainly in the UK's interest to leave.
