Polling is from 07.00 to 23.00, 50.7 million people eligible to take part.

On Sunday 4 December Italians go to the polls to vote in a referendum on a government-backed constitutional reform to abolish Italy’s existing parliamentary system in favour of a smaller senate of indirectly elected regional and local representatives with limited law-making powers.

The reform was passed definitively by parliament in April but on the request of MPs it is now being put to the popular vote before it can take effect. Unlike for a referendum to abrogate exiting laws, there is no quorum and only a majority of those voting is required.

In the referendum Italians are being called to answer 'yes' or 'no' on a question that reads: Do you approve the constitutional law to over-ride the bicameral system (of parliament), to reduce of the number of MPs, to contain the operating costs of public institutions, to abolish the National Council on Economy and Labour (CNEL), and to amend Title V of the Constitution Part II?

The CNEL is a 65-member advisory body on economic and social policies that many claim is useless, while Title V Part II covers Italy’s 110 provinces, which the reform aims to definitively abolish on grounds they are redundant and expensive.

The Yes campaign is being led by prime minister Matteo Renzi of the Partito Democratico (PD), who has staked his political future on the outcome of the referendum and may resign in the event of defeat. It has the backing of several key members of the Italian political establishment including former President Giorgio Napolitano and ex prime minister and president of the European Commission Romano Prodi. Captains of industry such as Fiat Chrysler Automobiles chief Sergio Marchionne and foreign leaders including US president Barack Obama have also given their support.

The No campaign is being driven by an assortment of opposition parties, including the anti-establishment Movimento Cinque Stelle (M5S), Forza Italia and the Lega Nord, as well as by a left-wing minority within Renzi’s own PD and some high-profile constitutional experts.

Opinion polls published before the two-week blackout period starting mid-November put the No vote consistently in the lead. However, in recent weeks the fragmented No campaign has appeared to lose momentum and the final outcome could be a close call.

In total 50,709,992 Italians are eligible to vote, of whom 3,995,042 overseas residents who have already cast their postal ballot.

Voting in Italy is from 07.00 to 23.00, with results expected early Monday.