When the eurozone had to rescue Greece and then Ireland last year, it marked the most turbulent 12 months in the history of the euro since its inception in 1999. The region started 2011 in an upbeat mood with the inclusion of Estonia as the 17th member of the single currency.

But, as the celebrations died down, it has become clear that Europe's economy is suffering from a massive debt hangover that could lead to more countries asking for help.