The idea of President Nicolas Sarkozy of France and Chancellor Angela Merkel of Germany getting together to jointly pen a begging letter conjures up a touching picture. These leaders have had their disagreements recently about how best to deal with the Greek problem but now they are united by a shared nervousness. They fear the weakness of their currency.

Evil speculators, they suspect, are lying in wait to deliver another pounding to a euro which has already fallen from around $1.5 just six months ago to now hover at $1.2, a level it has already breached this week. Hence the leaders' joint missive to European Commission President Jose-Manuel Barroso asking for tighter controls over trading in currency-linked debt and derivatives.