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 which sentenced the media mogul to four years in jail— commuted to 1 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 from public office. This will enable him to remain as a Senator and as leader of his center-right People of Freedom Party (PDL) for the moment.
He was convicted over the fraudulent purchase of broadcasting rights by his Mediaset television empire.
It was the 76-year-old media mogul's first definitive conviction in up to 30 court cases on charges ranging from fraud and corruption to having sex with an under aged prostitute.
He accuses leftist magistrates of relentlessly trying to remove him from politics since he stormed onto the scene in 1994.
(Read more: Top court asked to reduce Berlusconi ban)
The verdict could not only end the 76-year-old media mogul's 20-year domination of Italian politics but destabilize the three-month-old government of Prime Minister Enrico Letta and send tremors across the euro zone.
The bloc's third largest economy is ruled by an uneasy and fractious coalition of Letta's center-left Democratic Party (PD) and Berlusconi's PDL.
(Read more: Is the net closing in on 'Houdini' Berlusconi?)
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 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.