Silvio Berlusconi put his future on the line yesterday, announcing that he would resign if he was “caught lying” about his relationship to Noemi Letizia, 18, the aspiring model at the centre of the Italian Prime Minister’s divorce battle.

His version of events leading up to their meeting at Ms Letizia’s birthday party was immediately challenged, however, by a relative of the young woman. In an explosive interview, Francesca Palumbo, Ms Letizia’s aunt, contradicted Mr Berlusconi’s claim that he had known the Letizia family for a long time. As far as she was aware he only “came into the life of the family” last autumn, she said.

Mr Berlusconi and Benedetto Letizia, the father of the Naples woman, both claim that the Prime Minister is an old friend of the family and has known her since she was a small girl. Ms Letizia calls the Prime Minister “Papi” (Daddy).

Ms Palumbo’s statement supports the account of Gino Flaminio, Ms Letizia’s former boyfriend, who says that Mr Berlusconi contacted Ms Letizia on her mobile phone last autumn after she had sent modelling agency photographs of herself to Mediaset, his television company.

Mr Flaminio also told La Repubblica that she was no longer the person he knew after spending New Year at a party at Mr Berlusconi’s villa in Sardinia which lasted several days, and was attended by “thirty or forty” other young women. Mr Letizia has threatened to sue the paper and Mr Flaminio for defaming his daughter.

Mr Berlusconi said that if someone were to ask whether he had “spicy [piccanti] or more than spicy relations with an under-age girl”, his answer would be: “Absolutely not.”

“I have sworn it on the life of my children. And I have said that I am aware that, if this were perjury, I would have to resign a minute later.”

In an interview with La Repubblica Ms Palumbo, the sister-in-law of Anna Palumbo, Ms Letizia’s mother, said that towards the end of last year Ms Letizia left the table during a family lunch when her mobile phone rang.

“I heard her say ‘Papi’. I had no idea at the time who it could be.” She only realised for the first time that Mr Berlusconi was a “presence in the family” on January 11 this year, when she learnt that a “big party” was being planned for Ms Letizia’s 18th birthday in April and that Mr Berlusconi was expected to attend.

She said that Mr Berlusconi had asked Ms Letizia to give him the invitation personally. “I don’t know if Noemi went to see him in Rome.” At a family lunch during Easter, however, it had been confirmed that “we should all get ready because we were going to meet the Prime Minister”.

She said that she had decided to speak out now because there had been “too many lies”. She described the former boyfriend, Mr Flaminio, as a “good lad”. She said: “He really loved Noemi and she was very fond of him.”

Il Giornale, Mr Berlusconi’s newspaper, said that Mr Flaminio was a discredited witness because he had been given a suspended prison sentence in 2005 for stealing a mobile phone.

With the G8 summit at L’Aquila under his chairmanship approaching in July, insiders say that Mr Berlusconi fears “a repeat of 1994” — a reference to the G7 summit that year in Naples at which he was served with a court summons on corruption charges.

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