The Cannes summit leaves the world no further forward on its quest for some kind of solution to the Eurozone crisis. Strikingly, the Germans still won't agree — despite huge diplomatic pressure — to the ECB fulfilling the traditional emergency function of a central bank and acting as lender of last resort. This is a blow when you consider that Cameron thought there was a real possibility Merkel would budge on this after last week's European Council meeting.
It also provides Cameron with a domestic political headache. For if the ECB won't act, the IMF will have to take more of the strain — and increasing Britain's contributions to the IMF in the current political climate is not going to be easy. Ed Balls has already pitched his tent in the right place to draw as much Eurosceptic support as possible, arguing that the IMF can't be expected to fill in for the ECB.
The worry for Cameron is that the rebellion of the 81 last week is fast looking like the beginning of his parliamentary troubles over Europe not the end. He is going to have to do everything he can in the next few weeks to get ahead of this issue.