FACTBOX: Who might lead an interim Italian government?

(Reuters) - With Italian Prime Minister Romano Prodi forced to resign after losing his parliamentary majority, President Giorgio Napolitano must decide whether to call a snap election or try to install an interim government.

Napolitano would prefer to have an interim administration to reform the electoral system before holding a vote, in order to give future governments more stability, but it remains to be seen if there is parliamentary support for such a solution.

He would have to find a prime minister acceptable to a broad majority in parliament, including centre-right opposition leader Silvio Berlusconi who favors a snap election which he is confident he would win.

Here are some people considered possible candidates to lead an interim Italian government:

Franco Marini

As president of the Senate, the 74-year-old is already second only to Napolitano in the institutional hierarchy. With roots in both the trade union movement and the Christian Democrat party which dominated post-war Italy, the silver-haired Marini is a left-leaning Catholic centrist, a moderate who could gain broad consensus.

Gianni Letta

Cabinet undersecretary in the last Berlusconi government, Letta has been one of the centre-right leader's closest aides and might be the only person he would consider backing. The 72-year-old lawyer is respected by the centre left and has often acted as a diplomatic go-between in back-room talks between Italy's political grandees.

Giuliano Amato

Prodi's Interior Minister has already served twice as prime minister -- once in 1992 as the "Clean Hands" corruption probe destroyed several top politicians, and again in 2000-2001, taking over from Massimo D'Alema who resigned after a poor result at regional elections. The 69-year-old law professor would have the intellect to steer through election reform, but possibly not the necessary broad political support.

Mario Draghi

It would not be the first time that a Bank of Italy governor is called on to take charge during a political crisis -- Carlo Azeglio Ciampi headed a technical administration in 1993-94 and went on to be president. Draghi, 60, is a non-political technocrat but may prefer to stay in the relatively safe waters of central banking than venture into the political bear pit.

Mario Monti

Often touted in the press as a possible leader of Italy, the 64 year-old president of Milan's Bocconi University has managed to keep out of party politics. Governments of both right and left appointed him to the European Commission where he made his name internationally as head of EU competition enforcement, crossing swords with huge U.S. companies Microsoft and General Electric. Like Draghi, he may prefer to stick where he is.

(Reporting by Robin Pomeroy and Liz Rusbridger; editing by Sami Aboudi)