Seventeen eurozone countries signed-up forthwith, the remaining countries are inclined to do so but will consult their Parliaments first out of sheer democratic animal spirits. Except for the United Kingdom, whose Prime Minister displayed the brutal reality of Executive power in the United Kingdom's so-called democracy by refusing point blank to accept the greater interest of the European Union, or indeed of the United Kingdom, over that of his party's unity. A democratic leader would have consulted his country's Parliament on Lisbon Treaty changes.
Not even his government coalition's survival was at stake; there is a European majority in the UK Parliament. Cameron put at risk the economic security of most of Europe for a Conservative party faction. He wasn't defending City interests, despite his protestations, for City interests require the highest levels of representation within the EU and he has certainly lost that. Nor could anything prevent greater EU surveillance over the City's 'light touch' regulation; those glory days are gone. EU business will be regulated and (to a far greater extent than might have been with the UK properly represented) transacted within the core EU from now on. And it is impossible to imagine the European Union taking any repatriation of powers to the UK seriously after facing down the UK on an issue as important as the Euro itself.
Let us hope Cameron has the courage of others' anti-EU convictions and leaves altogther; there's nothing but a price to pay and Union meddling in the UK's internal affairs left for the UK in Europe now. No reason to stay and every reason to go.