The German government has been forced to hand over hitherto secret documents that expose the flaws of the euro - and the misgivings of European politicians - in the years before it became a reality.

Der Spiegel news magazine made a successful request for the release of the euro files at a time when the odds on Greece quitting the common currency within 18 months rise to 75 per cent and the chances of a complete shattering of the eurozone have never been higher.