Another week, another crisis, another round of pledges to restore the credibility of the single currency.

A week ago, the G20 summit in Cannes was being seen as the icing on the cake – an international stamp of approval on a European Union (EU) economic rescue deal giving Greece more bail-out money, coupled with a generous 50 per cent debt write-off and a shoring-up of Europe’s bank liquidity.

A week on, as G20 leaders fly out of Cannes, the deal is in doubt, the credibility of the single currency is worse than ever and world leaders are seething that their event was hijacked by a destabilising euro squabble that they say need never have happened.

Delivering a master class in the art of understatement this afternoon, European Commission president Jose Manuel Barroso surveyed the political and economic wreckage, and commented: “It’s true that the uncertainty that came after some announcements made in Greece were not helpful....we know that.”

He was referring to the ill-timed and totally unexpected announcement by Greek prime minister George Papandreou on the eve of the G20 meeting of a referendum on the latest bail-out offer to Greece, which the country had already apparently accepted.

Tonight, Mr Papandreou, who infuriated EU and G20 leaders, has withdrawn his referendum plan and is fighting for his political life in a confidence vote in Athens, leaving a trail of EU political and economic damage.

French president Nicolas Sarkozy, the G20 host, is furious that his grandstanding event was effectively ruined and that the hoped-for international financial support for Europe’s economic recovery plan never materialised in the midst of the Greek bombshell which threw the carefully-crafted EU deal into doubt.

This weekend, the real possibility of Greece leaving the euro zone is in the air, further undermining the currency’s credibility and reinforcing market uncertainty even though a euro zone split is still deemed unlikely.

The fall-out from the row is now reverberating across the EU and raising deep questions about the EU’s future direction and capacity to function effectively as a bloc.

The president of the European Council, Herman Van Rompuy, referenced the late British prime minister Harold Wilson today when he reflected on the last seven days of a growing economic nightmare.

He said: “We took our decisions (at an EU summit) a week ago: let’s be honest - a week can be a long time in politics, but for those kind of decisions it’s a very short one.”

Reflecting on the way financial markets have dogged EU efforts to find a lasting economic solution, he remarked: “It could be that the time-frame of the markets is different from the time-frame of democracies”.

US president Barrack Obama left Cannes making clear that he thought it was about time that European leaders got their act together.

But despite the outcome of a week all EU leaders would rather forget, Mr Barroso and Mr Van Rompuy joined in the ongoing efforts to talk up the euro’s fortunes, insisting the G20 meeting had been a “success”.

Mr Barroso commented: “We’ve responded (to the crisis) with determination to do what it takes to defend the euro.

“Around the (G20) there was a clear message of support - in some cases of admiration - for the commitment of the European countries in the face of this unprecedented situation that we have been facing.”

He added: “”We respect Greek democracy and Greece’s right to decide on its own future.

“At the same time, we need Greece to demonstrate commitment to the decisions that it has itself subscribed to.”

Mr Van Rompuy tried to steer the pair’s post-G20 press conference to wider issues, saying Europe’s core business remained the achievement of economic growth and employment.

But with questions still aimed at the fate of the battered euro zone and the fall-out from a European week from hell, Mr Barroso retorted: “I’ll say what I’ve said before: this (solving the euro zone crisis) is not a sprint, it’s a marathon - and marathon, by the way, is a Greek word.”

PA