Exit polls in Italy suggest the Prime Minister has suffered a heavy defeat in a referendum over constitutional reform.
Matteo Renzi has said he would resign if the Italian people reject his plan to reduce the role of the Upper House Senate and claw back powers from regional authorities.
A loss could plunge the country into political turmoil, which could have ramifications for the rest of Europe too.
Italian populist parties - including the anti-immigrant Northern League - have been waiting in the wings, banking on Renzi losing the referendum in the hope of seizing power themselves.
Renzi is due to address the nation at midnight local time (11pm GMT).
Another leader is toppled and the European 'establishment' now stand in terror of voters with 2017 set to host a series of big elections.
Italians go to the polls in a referendum on Sunday which could spell the end of Matteo Renzi's reign as prime minister.
Italians are preparing to vote in a pivotal referendum and one result could mean its PM resigns and send waves across the European Union.