The Czech Republic President has hit out at the eurozone bloc, saying the union has failed to bring meaningful economic benefits to its members.
Václav Klaus said over the last decade, the economic performance of eurozone countries has diverged and the negative effects of the "straight-jacket" of a single currency had become "more and more visible".
While these problems were not obvious during the 'good weather', they manifested themselves very clearly once the crisis or 'bad weather' arrived, he said.
"As a project that promised to be of considerable economic benefit to its members - the eurozone has failed," he said, in an article written for the Wall St. Journal.
Klaus made the damning criticism after months of turmoil of the single-currency area, in which members states have been forced to back a European Commission-led financial bailout of Greece.
Markets initially rallied on last month's €750bn EU rescue package, but have remained volatile on fears other economically weak member states such as Spain and Portugal could follow Greece's economic collapse.
Klaus said the proposed measures to save the euro would not bring "salvation" for the European economy.
"In the long run, it can be saved only by a radical restructuring of the European economic and social system," he added.
"My country had a velvet revolution and made a radical transformation of its political, economic and social structures.
"Fifteen years ago, I sometimes joked that after entering the EU we should start a velvet revolution there as well. Unfortunately, this ceases to be a joke now."
Friday marks the start of the G20 meeting of finance ministers and central bank governors in South Korea, in which Chancellor George Osborne will urge his counterparts, including from many EU member states, to follow his lead in taking tough measures to tackle their public deficits.
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