If it comes to pass, it will be the third big anti-establishment revolt by voters in a major Western country this year, following Britain’s unexpected vote to leave the EU and the US election of Donald Trump.

Matteo Renzi has vowed to resign if the “Yes” vote, which he has backed, loses.

Mounting pressure

Pressure is mounting on Renzi to drop his threat and agree to remain in power.

Commentators have said he will be needed to deal with the fallout from a “No” vote, including the risk of full-blown banking crisis.

US President Barack Obama urged Renzi to “hang around for a while, no matter what”.

What is the referendum about?

Last Italy referendum poll reveals Renzi to be DEFEATED in referendum in next blow for EU https://t.co/31G6DPPKMm

— Voice of Europe (@V_of_Europe) 27 novembre 2016

The referendum proposes constitutional reforms to strengthen the lower house of parliament and reduce the authority of the upper house or Senate.

Regions would lose some decision-making powers to bolster central government.

Renzi says the project is necessary to make
Italy governable enough to enact reforms needed to revive its moribund economy.

Opponents say it would reduce democratic checks and balances.

What the polls say

Opinion polls cannot be legally published in the final two weeks of campaigning.

However, the last 40 surveys released before the November the 18th cut-off showed the “No” camp ahead by up to 11 percentage points.

A source in Renzi’s Democratic Party (PD) says private polls suggest this gap will be closed to five points.

A quarter of voters are still undecided, meaning victory is still possible.

Initially, the plan was backed by 70% of Italians.

However, when an over-confident Renzi said at the end of 2015 he would resign if defeated, opposition parties turned the referendum into a de-facto ballot on his two-and-a-half years in office.

The third major anti-establishment shock of 2016 could be about to strike the globe https://t.co/hJZdV26uVZ

— The Independent (@Independent) 27 novembre 2016

Renzi’s record

Commentators say Renzi’s record is mixed.

Despite many reforms, Italy is set to have the third-lowest growth in the 28-nation EU in 2016, and the second-lowest next year, according to EU forecasts.

Unemployment is stuck above 11% and wages are stagnant.

What would a “No” vote mean?

It would be seen as more evidence of voter fury in Europe ahead of elections in France and Germany next year.

Renzi’s exit could also benefit the populist, ex-comedian Beppe Grillo, who wants to ditch the euro currency.

Grillo’s Five Star movement won more than a quarter of the vote in Italy’s last general election in 2013.

What they are saying

“My personal opinion is that Renzi should stay, what needs to be considered is what is good for the country,” – Industry Minister Carlo Calenda.

Matteo Renzi's reform sounds sensible. However, the details offend against democratic principles https://t.co/rO0Otm0VTS

— The Economist (@TheEconomist) 26 novembre 2016

“He (Renzi) is young and impulsive. If the result is terrible, he might decide to call it a day and something else with his life,” – an unnamed official.

“I am afraid that if he loses the referendum, (Renzi) really will give up. Italy can react to anything, but this really would be a step back,” – fashion designer Salvatore Ferragamo (Euronews)