BBC News with Iain Purdon

The centre-right opposition in Greece has demanded the resignation of the Prime Minister George Papandreou and called for snap elections, throwing into

disarray

plans for a unity government. Mr Papandreou had earlier suggested a coalition as a way out of the deepening political crisis. Greek politics has been in turmoil since Monday when the prime minister proposed holding a referendum on the latest European bailout and austerity plan. From Athens, here's Mark Lowen.

This has been a day of intense uncertainty and speculation in Athens. The prime minister addressed parliament to calm nerves. He raised the possibility that the referendum could be abandoned and last week's debt deal accepted.

"Of course if we had a consensus, then this would be an option, and we wouldn't have to go to a referendum. If the opposition is willing to negotiate, then we are ready to

ratify

this deal and implement it."

Mr Papandreou appears to be resisting calls to go, hoping that if the threat of a referendum fades he can yet steer this country through the crisis. Greeks and all of Europe are looking on anxiously. The

reverberations

of what happens in the next few hours will be felt far beyond Greece's borders.

The developments in Athens have overshadowed a meeting of the G20 in Cannes, where leading industrialised nations are discussing the eurozone debt crisis. Speaking at the end of the first day of talks, the French President Nicolas Sarkozy said he thought the message sent by France and Germany to what he called the Greek political class had helped people to focus on what was