A decision by Rudy Giuliani to answer a mobile phone call from his wife while delivering a presidential campaign speech threatens to damage his bid for the White House.

Mr Giuliani, the Republican front-runner, stunned an audience at the conservative National Rifle Association when, midway through his speech, his mobile phone not only rang, but he answered it. “Hello, dear,” he said in a lovestruck voice. “I’m talking to members of the NRA right now. Would you like to say hello?” Several members of the gun rights audience began to squirm in their seats.

Mr Giuliani listened to his wife, then laughed. “I love you, and I’ll give you a call as soon as I’m finished, OK?” He listened a bit longer. “Okay, have a safe trip. Bye-bye. I love you.”

Campaign aides later said it was a spontaneous, loving moment, with Mrs Giuliani boarding a plane in London. But it emerged that he has taken calls from her during speeches at least twice before during his campaign.

The incident occurred on Friday, but it was not until yesterday that it became clear what a blunder it was, renewing focus on one of the former New York Mayor’s greatest vulnerabilities: his personal life and past erratic behaviour.

The Wall Street Journal, in an editorial, warned him: “Mr Giuliani has run an impressive campaign so far . . . [but] the rap on his candidacy is that his personal history and behaviour are too strange for someone who wants to sit in the Oval Office.” It added: “Mr Giuliani doesn’t need more weird.” Frank Luntz, a Republican pollster, told The Times: “This is not helpful.”

Mr Giuliani’s wife, Judith Nathan, is his third, and has already been the focus of unflattering media profiles. His second wife discovered he was divorcing her when he announced it at a press conference. After the break-up of that marriage he moved in with a gay male couple. He had a penchant for cross-dressing comedy routines during his term as mayor. He is barely on speaking terms with his children.

The incident has refocused attention on Mr Giuliani’s personality at a time when he has been campaigning as the straight-shooting hero of the September 11, 2001, attacks on New York and a scourge of terrorists.

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