Italy's supreme court on Thursday upheld a jail sentence against Silvio Berlusconi for tax fraud in a devastating blow to the former prime minister that could throw the country's fragile coalition government into crisis.


After a three-day hearing, the five judges of the supreme court rejected Berlusconi's final appeal against the verdict handed down by two lower courts in Milan. That verdict sentenced the 76-year-old billionaire media mogul to four years in jail — commuted to one year under an amnesty.


But the top judges ordered a judicial review by a Milan court of the second part of his sentence, a five-year ban on holding public office. This will enable him to remain a senator and leader of his centre-right People of Freedom Party (PDL) for the moment.


He was convicted over the fraudulent purchase of broadcasting rights by his Mediaset television empire.


1st conviction in 30 court cases


It was Berlusconi's first definitive conviction in up to 30 court cases on charges ranging from fraud and corruption to having sex with an underage prostitute. He accuses leftist magistrates of relentlessly trying to remove him from politics since he stormed onto the scene in 1994.


The verdict could not only end Berlusconi's 20-year domination of Italian politics but destabilize the three-month-old government of Prime Minister Enrico Letta and send tremors across the eurozone.


The bloc's third-largest economy is ruled by an uneasy and fractious coalition of Letta's centre-left Democratic Party (PD) and Berlusconi's PDL.


The former premier has repeatedly said the government must not fall whatever the verdict, but PDL hawks had called for a mass walkout of its ministers and public protests, including blocking motorways with demonstrations, if he was convicted.


Supporters of the media mogul, known for his lavish lifestyle, womanizing and at times outrageous quotes, demonstrated outside his Rome home before the verdict, causing traffic disruption.


A greater threat to the government could come from the faction-ridden PD, many of whose members are already unhappy with ruling in coalition with Berlusconi's party and could rebel following his first definitive conviction.


Because of his age, Berlusconi can do community service or submit to house arrest instead of jail but the sentence is unlikely to take effect until the autumn because of bureaucratic delays.