The leader of Italy's centre-left opposition resigned yesterday after a regional election defeat to the party of Prime Minister Silvio Berlusconi, who has been consolidating his strength despite a deep recession.

Walter Veltroni confirmed his intention of quitting, a spokesman for his Democratic Party (PD) said, even after party bosses initially ruled out the possibility following their routing in the Governor's race on the island of Sardinia.

Analysts said the opposition had failed to capitalise on a grim economic recession, set to become Italy's longest since World War II, and was weakened by constant internal bickering and a string of corruption scandals.

"The economic crisis has started to bite the country. The paradox is that the responsibility isn't put on the government, but on its rivals," wrote columnist Massimo Franco, in a piece analysing Mr Berlusconi's victory for Corriere della Sera daily.

Mr Berlusconi had criss-crossed the Mediterranean island, where he has a luxury villa, campaigning to capture a region previously controlled by the centre left.

His party's candidate for Sardinia Governor, Ugo Cappellacci, the son of Mr Berlusconi's tax adviser, had 52 per cent of the vote by midday yesterday and was declared victor.

That compared with 43 per cent for rival Renato Soru, the former Sardinia Governor and founder of telecoms firm Tiscali, who had been tipped as a future leader for the centre left.

Mr Soru's defeat was the latest setback for Mr Veltroni, who was badly beaten by Mr Berlusconi in a parliamentary election last year. Since then, the opposition has been in disarray, while Mr Berlusconi's government enjoyed record popularity ratings despite the economic crisis.

Mr Veltroni, 53, had been at the helm of the PD since it was created in 2007 by merging the post-Communist Democrats of the Left and the more centrist Daisy Party to form a broad, single party that excluded the extreme left.

The former Rome mayor, a novelist and movie buff, had presented himself as the young, new face of Italian politics - borrowing his campaign slogan from Barack Obama's "Yes, We Can".

But after his crushing defeat to Mr Berlusconi in the April 2008 vote, he was increasingly accused by allies of lacking the authority needed to regroup the centre left and effectively allowing the 72-year old premier to rule unopposed.