Three-time premier Silvio Berlusconi has been sentenced to seven years in jail and banned from public office for life after a Milan court found him guilty of paying for sex with an underage prostitute and abusing his office to conceal the act.

The sensational conviction of the leader of Italy's centre-right was not unexpected. But the nation was this evening waiting anxiously to see how the tycoon would react - and whether the sentence would have serious repercussions for Italy's fragile left-right government of national unity.

Judges decided that Mr Berlusconi, 76, paid erotic dancer Karima El-Mahroug, whose nome d'arte is Ruby the Heart Stealer, for sex in 2010 when she was under 18 - a crime in Italy,

The billionaire was also found guilty of abusing his powers in trying to conceal the act. A recording played to the court showed him calling police and telling them Ms El Mahroug was the granddaughter of then Egyptian president Hosni Mubarak in order to have her released on the night of May 27 2010, when she had been held for suspected theft.

Mr Berlusconi, who was not in court to hear today's verdict, was no doubt hoping that the circumstantial nature of the evidence might provide a get out. But the three woman judges, Carmen D'Elia, Orsola De Cristofaro e Giulia Turri, were in no doubt about his guilt.

They not only convicted him on the sex charge and of abuse of office but dealt him a heavier sentence than that called for by the prosecution. The judges upped the request from six to seven years, and agreed to the prosecutors' demand for a life-time ban on him holding public office.

Both Mr Berlusconi and Ms El Mahroug have denied ever having sex. Mr Berlusconi has repeatedly claimed that Milan's judges are part of a leftist plot to oust him from politics.

He is entitled to two appeals before the sentence is executed. And as someone in his seventies, he almost certainly would not go to prison if definitively convicted.

Mr Berlusconi made no immediate comment. But pundits and Mr Berlusconi's supporters said today's verdict was a humiliating blow for a politician with aspirations of being an international statesman.

Renato Schifani, a senator and a senior member of Mr Berlusconi's PDL party, said the verdict represented "an injustice and pathological persecution" against the ex-premier.

Mr Berlusconi's lawyer Niccolo Ghedini said the verdict "was removed from reality, but not unexpected".

Ahead of the verdict, the chairman of the Senate justice committee, Nitto Palma, a Berlusconi ally, said the government was " not at risk over the trial. If he is found guilty he will behave responsibly, as promised".

But Massimo Giannini, the deputy editor of the centre-left La Repubblica newspaper, which led the exposure of the "bunga-bunga" affair, said the judges had dealt "an exemplary conviction" that was just punishment for the "whole web of corruption" constructed by Mr Berlusconi.

The sex crime occurred at Mr Berlusconi's mansion at Arcore outside Milan. Prosecutors said that regular dinners there degenerated into erotic dancing and sex sessions, for which the young female participants, including Ms El Mahroug were paid thousands of euros a time.

Significantly, the judges declared in their verdict that many of the witnesses -- including Arcore party goers - who gave testimony on Mr Berlusconi's behalf should be investigated for perjury.

In April 2012 last year records of bank transactions revealed that the billionaire media mogul had paid a total of €127,000 to three key witnesses shortly after the "Rubygate" trial had begun.

Protesters joined the world's media outside Milan's Palace of Justice courthouse today morning even as judges were deliberating on their verdict.

As news of the verdict reached the crowds outside, Berlusconi's fans responded with whistles to protestors' cheers. Two women carrying signs reading "Thank you Ilda Boccassini", the prosecutor leading the case against Berlusconi. Others shouted back that magistrates were "trying to eliminate him from politics".

Prior to the conclusion of the case the chairman of the Senate justice committee, Nitto Palma, a Berlusconi ally, said the government was “not at risk over the trial. If he is found guilty he will behave responsibly, as promised.”

Massimo Giannini, the deputy editor of the centre-left newspaper La Repubblica, which led the exposure of the “bunga-bunga” affair, said the judges had dealt “an exemplary conviction” that was just punishment for the “whole web of corruption” constructed by Mr Berlusconi.

Trials and tribulations: Silvio in court

Mills Bribery Case

Launched Trial began in March 2007.

Key players Silvio Berlusconi and David Mills.

Background Mr Berlusconi was accused of paying British lawyer David Mills, the estranged husband of the former Olympics Minister Tessa Jowell, $600,000 to lie under oath on the mogul’s behalf in two corruption trials in the late 1990s. Mr Mills was sentenced in February 2009 to 4-1/2 years in jail for accepting a bribe.

Where are we now? Criminal charges against Mr Mills were thrown out in February 2010, when the final appeal expired under the statute of limitations. The charges against Mr Berlusconi met a similar fate, expiring in February 2012.

Fininvest Case

Launched Trial began in October 2009.

Key players Silvio Berlusconi, Cesare Previti, Carlo De Benedetti.

Background Fininvest, the holding company for Mr Berlusconi’s Mediaset TV empire, was dealt a severe financial blow in 2009 when a court ordered it to pay a rival company more than €750m (£642m) in compensation, subsequently reduced to €500m. The Milan court ruled that the CIR holding company of rival mogul Carlo De Benedetti, pictured left, was entitled to the payment because one of Mr Berlusconi’s lawyers and close associates, Cesare Previti, bribed a Rome judge in a takeover battle between the tycoons as they sought to gain control of the Mondadori publishing house in 1991.

Where are we now? Mr Berlusconi himself was cleared of involvement in the corruption. The final compensation verdict is due soon.

De Gregorio case

Launched Allegations made in February 2013.

Key players Silvio Berlusconi, Sergio De Gregorio.

Background In February magistrates said Mr De Gregorio, a former senator, had admitted to accepting €3m from Mr Berlusconi in exchange for swapping sides in parliament in 2006 – causing the collapse of the centre-left government of Romano Prodi and allowing Mr Berlusconi back into power. Mr De Gregorio, below, was elected to the senate as a member of the centre-left anti-corruption Italy of Values (IDV) party. He shocked party colleagues soon after, however, by quitting and aligning himself with Mr Berlusconi’s People of Freedom party (PDL).

Where are we now? Magistrates in Naples last month called for Mr Berlusconi’s indictment.

Mediaset Fraud Case

Launched Trial began in November 2006.

Key players Silvio Berlusconi, Mediaset executives.

Background In this, Mr Berlusconi’s most dangerous case, he is accused of tax fraud in relation to the purchase of US film rights for his television company, Mediaset. Milan magistrates claim that beginning in the 1980s, Mr Berlusconi’s holding company Fininvest, and subsequently his broadcast group Mediaset, registered inflated costs for the purchase of US film rights, in order to divert millions of euros to overseas slush funds. In May this year an appeal court confirmed his 2011 conviction that saw him sentenced to four years in prison and banned from holding public office for five years.

Where are we now? The final appeal verdict is due by the end of the year – if Mr Berlusconi loses, he will be barred from public office.