Renzi to meet President Mattarella.

The attempt of Matteo Renzi's government to reform the Italian constitution was decisively defeated in a referendum on 4 December. On a larger than normal turnout for a referendum those voting No won by about 60 per cent compared to the 40 per cent of those voting Yes.

In one of his shortest speeches ever Renzi announced just an hour after the polls closed at 23.00 that he would offer his resignation to President Sergio Mattarella on the afternoon of 5 December.

The defeat of the reforms to the constitution, which mainly regarded the senate, can be partly put down to the fact it was a messy measure that never quite won the confidence of many constitutionalists. While it opened up the possibility of a faster and more efficient legislative process it also handed considerably more power to the executive, something that has always been looked on with suspicion in post-war Italy.

The defeat can also be put down to the prime minister himself. His almost three years in office has been characterised by his high-handed treatment of opponents, particularly those within his own party, the Partito Democratico, which he never bothered to get solidly behind him. The disdain of the young prime minister in a hurry (he was 39 when he took office) for the party's old guard and his neglect of its grass roots organisation did Renzi no favours.

The painfully slow pick-up in the economy – despite Renzi's much-needed labour reforms and his initially popular fiscal handouts – plus the persistently high level of unemployment among the young, also added to the No vote, as did growing concern about the financial and social costs of immigration across the Mediterranean.

Renzi's decision to pin his own political future on the success of the referendum was also a miscalculation. Made months ago, at a time when his reforming zeal was still considered the best way to get Italy moving again, he decided to make the referendum a vote of confidence in his government, saying that he would resign if the reforms failed to pass. Once said it was difficult for him to backtrack.

His resignation opens up months of political and economic uncertainty. The right-wing populist movement Movimento5 Stelle, which led the No vote, will now be claiming another victory to add to its considerable success in local elections last the summer. The ageing ex-prime minister Silvio Berlusconi will be manoeuvring for a position as kingmaker. And the right-wing, anti-immigrant, anti-European Union Lega Nord will also be glowing with success.

The decision of what happens post-Renzi now depends on President Mattarella.