John Lipsky, the acting managing director at the IMF, on Tuesday said a key challenge in post-crisis Europe was the ability to sustain international policy cooperation.

At the Kurt Viermetz Lecture at the American Academy in Berlin, Germany, Lipsky said: "Greater cooperation and coordination here in Europe will be an essential element in overcoming the serious threats to the region's stability and progress, and in completing the single-market project."

Lipsky said the global economy was now more