Italian Prime Minister Matteo Renzi is facing defeat in a constitutional reform referendum that could spark the European Union’s next crisis.

Mr Renzi has promised to resign if voters reject proposed reforms to the Italian Senate, thus increasing political uncertainty in the Eurozone’s third largest economy.

Final polls out this weekend show the “No” camp widening its lead after the election of Donald Trump in the United States, with voters increasingly keen to punish the political elite and Mr Renzi looking increasingly beleaguered.

The vote is still two weeks away, but a polling blackout will now apply, prohibiting the publication of any new opinion polls before the referendum.

The reforms include limiting the Senate’s powers to veto bills and taking more power from the regions and handing it to the central government.

The Italian government had hoped these measures would lead to greater stability in a country where administrations regularly come and go in the space of a few years, but disillusioned voters have seized on Mr Renzi’s threat to resign if the referendum fails and rapidly turned against him.

Alessandra Ghisleri, head of the Euromedia agency, told Reuters: “Trump’s victory was important because Renzi strongly backed Hillary Clinton and so people link him with the loser and the mainstream establishment that Clinton was seen as representing.”

Renato Mannheimer, head of Eumetra-Monterosa, which gives ‘No’ a seemingly unassailable 12-point lead, also told the news agency: “It’s all about disenchantment with Renzi because the economic crisis isn’t finished and the lives of most Italians aren’t improving.

“I don’t think it has much to do with the constitutional reform itself.”

Another survey by Ipsos-PA for Corriere della Sera gives ‘No’ a 10-point lead, while Euromedia puts the ‘No’ side eight points ahead.

Mr Renzi’s resignation could pave the way for fresh elections in Italy, which could see the insurgent populist Five Star Movement take power. The party now polling just behind the governing Democratic Party, potentially giving it enough support to lead a centre-right coalition.

The party is strongly Eurosceptic and anti-establishment, thus creating another headache for European leaders.