Germany was forced to agree to bail out Greece for the second time in a year under strong pressure from the International Monetary Fund following the resignation last month of its head, Dominique Strauss-Kahn, the Guardian has learned.

Under its acting chief, the American John Lipsky, the IMF has taken a more hardline stance. The fund warned the Germans in recent weeks that it would withhold urgently needed funds and trigger a Greek sovereign default unless Berlin stopped delaying and pledged firmly that it would come to Greece's rescue.

Senior officials and diplomats in Brussels confirmed that the IMF threat to pull the plug on its funding, in stark contrast to the more emollient line of Strauss-Kahn, had been defused because of a German climbdown.