Tens of thousands of people poured into the piazza in front of Milan’s landmark cathedral late Monday and partied into the wee hours after the unbelievable drubbing dished out to the Italian prime minister Silvio Berlusconi in the city’s local elections and others across the country at the weekend.

There was shock and disbelief across the political spectrum when the centre-right lost control of the nation’s financial capital for the first time in 20 years.

The centre-left Democratic Party’s candidate Giuliano Pisapia easily defeated Berlusconi’s ally, the incumbent mayor Letizia Moratti  — winning 55.1% of the vote to the lacklustre Moratti’s 44.9% — in a run-off election called when the first ballot failed to deliver either candidate an outright majority.

Berlusconi was also routed in the north-east city of Trieste and the Sardinian city of Cagliari while a former magistrate aligned with the left-leaning Italy of Values Party stormed to victory in the southern city of Naples.

Left-leaning newspapers heralded a political “tsunami” while Il Giornale, the newspaper owned by the prime minister’s brother, ran an ambiguous  headline  “Great Psychodrama” while warning the victors would promote an invasion of Roma gypsies and Islamists.

It was a devastating result for the Italian prime minister who really used these local elections as a poll on his own personal popularity and was also pummeled when he put himself on the local ticket in Milan.

The elections were perhaps the first real test of what voters thought of the charges he had s-x with an underage prostitute we all know as Ruby the Heartstealer  in a case that resumed in Milan yesterday and three ongoing fraud and corruption trials .

Berlusconi’s party even lost control of the local council in Arcore, the town outside Milan with the luxury villa where the prime minister allegedly held his notorious “bunga bunga” s-x parties with aspiring models and showgirls last year.

Milan is Berlusconi’s home turf where he built a billion dollar property and media empire and bought one of the country’s top football teams AC Milan before entering politics in 1994. It has also been an important power base not only for the 74-year-old but for his centre-right People of Freedom Party.

The prime minister looked grim when he faced the media in, of all places, Romania.  Well away from his domestic constituents, he was stoic but warned the wayward voters that they would be sorry and that they should pray to God to save them.  He could use a few prayers himself. But the combative premier still had time for a joke on Tuesday, saying “I tried to arrange my funeral but I have too many engagements in the next few days so I have delayed it.”

Those words could well be a prophesy. Many of  Berlusconi’s opponents are calling for his resignation but he is unlikely to go in the short-term.

Yes, there is certainly evidence of voter fatigue and many people are hurting economically. Recent figures from the Italian statistics agency ISTAT showed that the economy had grown by only 0.1% in the first quarter, while youth unemployment is now about 29% and even worse in the south.

Italy’s outgoing central bank governor Mario Draghi also raised the stakes on Tuesday when he accused “successive” governments of failing to implement economic reforms and took a swipe at the government for failing to rein in public spending.

The future of the prime minister is likely to rest with his Coalition partner the anti-immigrant Northern League, who also had a share of electoral setbacks in its northern heartland at the weekend.

Pundits say the League will be pushing for a cabinet reshuffle and the passage of its pet reforms such as financial decentralisation after the local-election vote, in which its supporters say it was brought down by its partner’s woes.

But whatever happens in the short-term, there are few gamblers in Italy today willing to bet on Berlusconi seeing the end of his term in 2013.