Rome, April 25 - Ex-premier Silvio Berlusconi said Thursday the idea of Enrico Letta failing in his bid to form a government was unthinkable given Italy's need to tackle a worsening economic and social crisis. "I don't even want to think about the idea of a failure. We need a government that does (things). And now. The economy is in terrible shape," said the three-time premier. Italy is in its worst recession for 20 years with millions facing poverty and unemployment hitting new heights. Letta is trying to get his Democratic Left (PD) party to agree to a grand coalition with Berlusconi's People of Freedom (PdL) party, an idea he has been pushing since the inconclusive February 24-25 general election. Many in the PD's left wing view a deal with arch enemy Berlusconi as anathema.