Gone midnight - and the night feels young

Just down the corridor 27 national leaders are having dinner and talking. Think of the discussions that go on around your dinner table and how long they can take. Now imagine there are 27 of you.

A few hours ago I went for some food in the canteen here and something struck me. The sauce and condiment table. Cider vinegar. Tabasco. Sherry vinegar. And good old Worcestershire sauce. At that point I thought I had better move on because the queue was getting a bit big behind me. But there were plenty more. It struck me as a symbol of the lengths the European Union has to go to placate the sensibilities of such varying national tastes and interests.

Scale that up to a currency - and even the global economy - and little wonder these things take time. European cooperation and integration has always been messy. But, in the midst of a humdinger of a crisis, it gets super messy. Click here to read Nick Robinson's fascinating insight into how the negotiations work, and how tricky it is for the Prime Minister.

Outside the leaders' room, here in the press room there are all sorts of theories and all sorts of draft conclusions flying about. But in short, whilst the leaders talk, we are pretty clueless.

Whatever happens, the European Union won't be the same again. At least part of it could look and feel like something approaching a super state. And so the UK's often uneasy relationship with the EU will change. And that, in two sentences, is why all this matters.

What would you regard as a good result for the UK? Should David Cameron be banging the table and taking this moment as an opportunity to bring powers back to Westminster? Or is now the time to focus on the saving the Euro? Can - and should - he attempt both?

Chris Mason is 5live's Political Reporter. You can follow Chris on Twitter - @ChrisMasonBBC.