Beppe Grillo's anti-establishment 5-Star Movement said on Sunday it wanted to lead Italy's next government following last month's inconclusive election and reiterated that it would not agree to an alliance with any other party.
The movement's newly elected parliamentary leaders told reporters it would make this position clear to President Giorgio Napolitano when he begins consultations later this month on the formation of a government.
"Our proposal will be a 5-Star government," the movement's Senate leader Vito Crimi said after a meeting of its lawmakers in a Rome hotel.
It is unlikely that the other parties would accept a government led by the 5-Star Movement. This is partly because of policy differences and partly because although it was the most voted single party at the election, 5-Star has fewer seats in parliament than the center-left and center-right coalitions.
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5-Star's policies include a minimum income for the unemployed, free Internet access for all, electoral reform, the abolition of state financing for parties and newspapers and the scrapping of work on a high-speed train line in northern Italy.
It campaigned on a radical platform to clean up politics and save the environment. Grillo's party has been under intense pressure to form an alliance with the center-left Democratic Party (PD) after the election produced a hung parliament, but it has insisted it will not guarantee its backing to any coalition.
The PD says it shares some of 5-Star's positions but its policies are generally less radical and there are significant differences, particularly regarding Europe. Grillo has called for an on-line referendum on Italy's membership of the euro zone.
Grillo said on Sunday he would withdraw from politics if his movement ever gave a vote of confidence to a government led by the center-right or center-left.
The center left bloc led by the PD won a lower house majority but failed to do so in the Senate, while 5-Star unexpectedly emerged as Italy's largest party in its first national election.
Parliament convenes on Friday and shortly afterwards Napolitano will begin consultations with party chiefs to try to find backing for a coalition.
Crimi and lower house leader Roberta Lombardi said 5-Star would tell Napolitano it can form a government on the basis of a 20-point program which it is still drawing up, but it would not initially propose any candidate for prime minister.
"If the president accepts our 20 points then at that point we will be ready to propose a name for prime minister," Crimi said.
Lombardi said 5-Star would be happy to work with any other party that accepts the 20 points, but will not give a vote of confidence to a coalition led by any other party.
"It's the program that creates the alliances not the other way round," said Lombardi.