Getty Italy PM Matteo Renzi is under increasing pressure ahead of the referendum

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The anti-corruption party, which wants to hold a “consultative referendum” on the euro and victory in the first vote could pave the way for that. It comes as current prime minister Matteo Renzi comes under increasing criticism for his links to the EU. And anti-establishment protestors clashed with police in Florence yesterday over the upcoming referendum.

Getty Five Star's Luigi Di Maio, whose party is against the Euro

Luigi Di Maio, one of the party’s prominent leaders, is poised to start a 10-day whistle-stop tour of various European cities in an attempt to gain the support of three million Italians living abroad. Mr Di Maio will head to London on Tuesday with stops in Madrid, Brussels, Paris and Berlin. In the last national election in 2013 Five Star won the most domestic votes in Italy but dropped into second place by the Democratic Party once the votes from those outside the southern European country were included.

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The 30-year-old, who is tipped to be the party’s prime ministerial candidate at the next general election in 2018 is aiming to prevent a repeat performance. He told Reuters: "We want to explain the risks of this reform to Italians abroad because if 'Yes' wins we will never get rid of the political class that forced them to emigrate.” A victory for Five Star would very likely set off seismic changes in Italian political life which would put the country on a potential collision course with the EU and next to leave the crumbling bloc.

Getty Italy's Prime Minister Matteo Renzi arrives in Brussels for talks with the EU

Mr Renzi has said that he would resign if he lost the vote on December, 4 but recently he has declined to confirm that, saying any discussion of his future would deflect from the constitutional reform. Through the vote, MrRenzi wants to reduce the role of the Senate and curb the power of the regional governments, claiming that the move will simplify decision-making and help produce more stable governments. However, critics have indicated that the proposed changes will actually make the political process more complicated and remove some checks and balances. Di Maio, whose party is roughly level with the incumbent Democratic Party, according to recent polls, said: “This reform will give more power to the people who have brought our country to the state it is in.”

Getty Five Star supporters hold placards that read: "The mess is served"