The Telegraph quotes Open Europe's Stephen Booth;
“Today’s developments are a boon to those who would like to see the UK leave the EU, and for good reason,” said Mr Booth. “This type of political agreement, so readily jettisoned in a moment of Eurozone panic, is precisely the type of agreement Cameron may, at least in part, be relying on to secure his negotiations and sell them to the British public. This episode will only increase the domestic pressure for the UK to secure treaty changes to underpin EU reforms.”So Cameron's task now becomes either Treaty change, or supporting Brexit. Good. Glad that's clear.