Rome, March 18 - Cracks have appeared the 5-Star Movement's (M5S) hard line after a handful of the anti-establishment group's lawmakers defied orders and voted for the centre-left's candidate to be Senate speaker at the weekend. M5S leader Beppe Grillo, who is hostile to the established parties and had ordered his movement's Senators to abstain, was furious, saying there would be consequences for the rebels. After inconclusive votes on Friday, Pier Luigi Bersani's centre-left alliance managed to get both of its candidates elected as Speakers for the House and Senate, Italy's third- and second-highest institutional roles respectively behind the president. After failing to reach an agreement for a consensus candidate, the centre-left had no trouble getting Laura Boldrini, a former spokeswoman for the UN High Commissioner for Refugees, elected into the key position in the House. However, the centre-left, which came first in last month's general election but failed to win a working majority in the Senate, was not sure of being able to carry the day in the Upper House. In the first rounds of voting the Senators belonging to the M5S, which holds the balance of power in the Upper House after capturing a massive protest vote last month, backed their own candidate. But when it came to Saturday's run-off between the two frontrunners, some M5S Senators opted to back the centre-left's man, former chief anti-Mafia judge Pietro Grasso, rather than run the risk of seeing Renato Schifani, the candidate ex-premier Silvio Berlusconi's centre right, keeping the job he held in the previous parliamentary term. Three M5S Senators have admitted voting for Grasso. The outcome shows comedian-turned-politician Grillo, who has not been elected himself, may have problems imposing discipline on his novice lawmakers. Nevertheless, experts say it is still unlikely that Bersani will manage to convince enough M5S Senators to win a confidence vote in a government led by him and break the political deadlock the country is currently embroiled in. Bersani has tried to win the M5S over with an eight-point platform reflecting many of the movement's policies, including cuts to the number of parliamentarians and other measures to reduce the cost of politics. Grillo, who says Bersani's Democratic Party (PD) is part of a corrupt, malfunctioning system that he wants to revolutionise, has responded with insults, which have included him describing Bersani as a "dead man talking". With Bersani ruling out the hypothesis of forming a grand coalition with Berlusconi's People of Freedom (PdL) party, the prospect of Italy having to return to the polls later this year seems likely. President Giorgio Napolitano is set to start consultations with party leaders on Wednesday, after which he will ask one of them, probably Bersani, to try to form a government.