Is the net closing in on 'Houdini' Berlusconi?

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The final verdict in Silvio Berlusconi's tax fraud trial, expected on Tuesday, could see the billionaire politician and media mogul banned from holding public office for five years.

This would have widespread implications for Italy's coalition government, headed by Prime Minister Enrico Letta, which relies on the support of Berlusconi's People of Liberty (PDL) party.

"The net is closing in on Berlusconi," John Foot, professor of Modern Italian History at London's UCL university, told CNBC ahead of the judgment. "A guilty verdict seems inevitable to me at this point, but in Italy anything is possible. If he's banned from office, it doesn't mean his political weight will disappear overnight but this is the beginning of the end of his political career I'm sure."

(Read more: Silvio Berlusconi's 'greatest' hits)

Foot said Berlusconi's lawyers would try "every trick in the book" to get him off. On Sunday, Berlusconi said he would not flee Italy and was ready to go to jail rather than face house arrest or community service if a court upholds his conviction.

"There's even talk of a political amnesty for Berlusconi. They'll say that this government will fall unless we save Berlusconi, but I can't see Letta being able to sell that one to his party base of the electorate," he added.

This is the last of Berlusconi's appeals against a four-year sentence - and a five-year ban from public office - for tax fraud involving his media company Mediaset, that was handed to him in May. He has repeatedly denied any wrongdoing.

(Read more: Prisonfor Berlusconi? Don't bet on it)

But Foot said a jail sentence was unlikely for the 76-year-old former Italian leader, who has avoided convictions for previous allegations involving bribery, mafia association and false accounting. He will "fight" to prevent being kicked out of the political arena, Foot added.

The final verdict in the trial was due in November but was brought forward to avoid part of the case collapsing due to a statutory limitation, an expiry date for legal proceedings that has been used in the past by Berlusconi's lawyers to get cases overturned.

"Mr Berlusconi has been the Harry Houdini of Italian politics. The fact that he's still a dominating force after February's inconclusive election, and that his legal woes threaten to bring down Mr Letta's government, are a reminder of just how little has changed in Italian politics," Nicholas Spiro, head of consultancy Spiro Sovereign Strategy, told CNBC.

(Read more: Is Italy on a collision course with Europe?)

"If Mr Berlusconi's sentence is upheld, the Senate would still have to vote to strip him of his parliamentary immunity in order for the ruling to be enforced."

That would be a lengthy process that could take up to ten months, Wolfango Piccoli, managing director of advisory firm Teneo Intelligence, said.

But Piccoli added that despite this, it was unlikely that Berlusconi would try to trigger early elections.

Berlusconi's party is currently ahead in the polls – which Foot described as "almost unbelievable" given his recent sentence to seven years in jail for abuse of power and sex with a minor.

(Read more: Berlusconi sentenced to 7 years for Abuse of Power, Sex With Minor)

Though some members of Berlusconi's party have threatened to resign if he is convicted, the analysts agreed it was not in Berlusconi's interest for his party to "pull the rug" on the coalition.

"Paradoxically, the biggest threat to Letta's government is more likely to emanate from members of his center-left Democratic Party (PD) and not from the PDL if Berlusconi's conviction is upheld," Piccoli said. "Letta is already facing growing uneasiness within the PD over the coalition deal with the PDL."

(Read more: Why Italy could be the next 'Bad Boy of Europe')

Tensions between the PDL and PD have grown in recent weeks over planned tax increases, with Berlusconi's party threatening to withdraw from the coalition if tax rises are not blocked.

"The government is becoming more and more untenable now- no one can see the point of it as they're not doing anything," Foot added. "Being in a coalition with a man convicted of tax fraud? That would make it even more so. But remember this is Italy, so anything is possible."

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