The editor of Italy’s national Catholic newspaper has resigned after “defamatory” media attacks which claimed he was gay.

Dino Buffo, the editor of Avvenire, the newspaper of the Italian Bishops Conference, had criticised Italian prime minister Silvio Berlusconi for his “immoral” lifestyle.

Berlusconi has been plagued in recent months by allegations of extra-marital affairs. His wife Veronica Lario filed for divorce earlier this year.

The attacks on Buffo’s character were led by Vittorio Feltri, the editor of Il Giornale, which is owned by the Berlusconi family.

In a front-page campaign, Il Giornale claimed Buffo was gay and had been involved in a scandal involving an alleged male lover in 2004.

According to the newspaper, Buffo paid a fine for allegedly harassing a woman over the telephone. It alleged she was the wife of his lover.

Buffo has admitted being fined in the case but denied he was sexually involved with the man.

In a rebuttal published this week in Avvenire, he said the slurs had ruined his family and “violated” his life. He added that he was resigning to protect his family.

Buffo has been backed by the Vatican, which issued an immediate statement supporting him.

Although both the Vatican and Berlusconi’s government had denied rumours of a rift, plans for a meeting in the papal city of Viterbo this weekend between the prime minister and the pope were cancelled.

Commentators have speculated that conservative bishops have been damaged by the scandals and the attacks on Buffo. All Italian leaders need the support of the Catholic church.

Berlusconi is currently suing at least two Italian and two foreign newspapers for their coverage of the scandals surrounding him.