Silvio Berlusconi was poised to make a remarkable political comeback last night after the collapse of the Italian Government led by Romano Prodi.

Only 20 months after defeating Mr Berlusconi in a close-fought general election, Mr Prodi, 68, fell from power in a senate confidence vote, losing by 161 to 156. The Prime Minister went immediately to the Quirinale Palace to tender his resignation to President Napolitano.

An exultant Mr Berlusconi held a celebratory champagne party at the Palazzo Grazioli, his residence in the historic centre of Rome, after hearing the news. “We need to go to the polls in the shortest time possible without delay,” he told reporters.

However, the ambitions of the flamboyant media tycoon, whose centre-right political movement enjoys a comfortable poll lead, may yet be frustrated by the President, who will begin consultations today on how to proceed. He could decide to appoint a caretaker administration to overhaul the Italian electoral system before new elections are held. Walter Veltroni, the leader of the largest party in government, argued last night that early elections would “push the country into a situation of dramatic crisis.”

Mr Veltroni, regarded as Mr Prodi’s successor in waiting, is said to want an interim administration and a new electoral law to give the Left time to prepare for the battle with Mr Berlusconi.

Mr Prodi, fighting to stay in power against the odds, had opened the confidence motion debate in the senate by appealing to senators to back him so that he could complete “urgent reforms”. In a reflection of the tense atmosphere, a senator from the Christian Democratic faction — the party that sparked the crisis by deserting Mr Prodi’s coalition — fainted after being assaulted by fellow party members when he declared that he was supporting Mr Prodi after all. In extraordinary scenes, Nuccio Cusumano was spat on and insulted and had to be taken out of the chamber on a stretcher. He later returned, but his vote was not enough to save Mr Prodi.

President Napolitano can now call new elections, appoint an interim caretaker government or ask Mr Prodi to try to reform his coalition, as he did when the Prime Minister lost a senate vote a year ago on the deployment of Italian troops in Afghanistan. Potential candidates for the post of caretaker Prime Minister would include Mario Draghi, the widely respected governor of the Bank of Italy.

Mr Prodi, who had gone ahead with the vote despite the prospect of defeat, said that he had done so in the spirit of the founders of postwar Italy, who had devised a democratic constitution whose 60th anniversary is being celebrated this week. This provided for votes of confidence to confirm or dissolve governments, and not for “extra-Parliamentary crises”. He said that Italy could not afford the luxury of a power vacuum.

Opinion polls indicate that the Centre Right would win elections handsomely. Mr Berlusconi has already fought four elections as centre-right leader, winning two of them, and a fifth election bid for the premiership would be an Italian record. Mr Prodi’s problems were sparked by the resignation last week of Clemente Mastella, head of the UDEUR Christian Democratic faction, as Justice Minister after magistrates began a corruption investigation involving him and his wife, Sandra. Some on the Left have accused the Vatican of persuading Mr Mastella to sabotage the Prodi Government — the 61st since the Second World War — because its policies on issues such as abortion and gay civil unions are against Roman Catholic doctrine. Vatican officials and Mr Mastella deny this.

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