How long can he last? Italians are asking this question of Silvio Berlusconi. His preferred answer is: for ever. Mr Berlusconi and his supporters are toughing it out, as in all previous scandals since he entered politics 15 years ago.

“This will not stop me,” the Prime Minister said as he visited L’Aquila, the venue for next month’s G8 summit. “I will not be overthrown by a subversive plot.”

Italians, the centre Right argues, know his failings. The problem is that the supposed plot grows daily more fiendish. It is already alleged to encompass the Left, the newspapers La Repubblica and Corriere della Sera, magistrates, El País, the Spanish newspaper that has published photographs of Mr Berlusconi’s parties, and the Italian magazine Oggi, which is due to publish photographs of Ms D’Addario, the latest showgirl to enter the fray, and Rupert Murdoch, chairman of News Corporation, parent company of The Times.

There is dismay among Mr Berlusconi’s supporters, moreover, that Niccolo Ghedini, his lawyer, sought to deflect Ms D’Addario’s allegations by arguing that even if they were true, the Prime Minister was only “the end user” of her services, and therefore committed no crime.

That message is not likely to go down well in Catholic Italy. Antonio Polito, a former senator and editor of the left-wing paper Il Riformista, predicts that “the worst is yet to come”, with the latest disclosures raising the question of whether the Prime Minister is “blackmailable”.

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