There was an astonishing theatrical display from Italian prime minister Silvio Berlusconi on Wednesday —  only a day after a Milan judge ruled he should stand trial on allegations he had s-x with an under-age pr-stitute we all know as Ruby and sought to have her released from custody after she was arrested on a theft charge.

His lawyers said they were expecting it but the speed and efficiency of the prosecutors’ action and the judge’s endorsement has shaken Berlusconi and his closest advisers.

With a solemn look on his face, the 74-year-old leader strode into a packed media conference at Palazzo Chigi in Rome, with his dyed hair plastered in place and his face caked in make-up for the TV cameras.

Flanked by his dour finance minister Giulio Tremonti, Berlusconi  looked like he was feeling the strain of many a “bunga bunga” party or at least the media’s obsession with the sordid soirees he allegedly hosted in the subterranean pole-dancing retreat at his luxury villa outside Milan.

Never mind the generous financial incentives he was offering to struggling Italian businesses, the media had gathered to hear his response to the claims he had offered the teenage Moroccan dancer Karima El-Mahroog, known as Ruby the Heartstealer, a few cash incentives of her own when she was only 17.

That morning the Left-leaning daily, La Repubblica, had published new excerpts from Ruby’s exchange with prosecutors last year in which she spoke about a €50,000 payment she had received from the prime minister.

While she initially lied about her age and said she was 24, Ruby reportedly told them she had later informed the prime minister she was in fact a minor — as he was about to offer her a rent-free apartment in a Milan complex known as the “Dolls House” where a dozen party girls were housed.

The prime minister has always denied paying for s-x and Ruby told a interviewer on the billionaire leader’s own TV network that he “never laid a finger on me” even though he gave her designer clothes, expensive jewellery — and cash payments.

But back to the embattled leader’s performance.  First we heard about the government’s “grande successo” and the need for an “optimistic” economic outlook from one of the country’s richest men.

This was only the first act.  Berlusconi soon warmed to his audience and switched on the charm for the cameras. For no apparent reason, he was dishing out smiles and smirks as his finance minister spoke about infrastructure and the need for nuclear power.

The cameras whirred while members of the foreign press questioned his state of mind, and any reporter who asked about the forthcoming court case was immediately silenced.

“Out of love of my country, I won’t talk about this,” Berlusconi told reporters. “I can only say one thing: I’m not worried at all.”

Well the prime minister may scoff but, according to one poll, this scandal has taken his popularity to a new low of about 35% and members of his People of Freedom party are privately expressing concern — even flagging alternatives.

Berlusconi’s lawyers may be skilful enough to keep him out of court on April 6 but he is facing a potential jail term of 15 years for these two charges.  And this court case is certain to impact the prime minister’s longevity like none of the other 100 cases he claims to have survived.