If Sarah Palin wants to run for President she will have to find a way to silence a 19-year-old ice hockey player who says that he is just “doing my thing” but appears to be out to destroy her.

Levi Johnston, whose laid-back Alaskan drawl belies the poison in his words, will pose for Playgirl magazine next month on the day that Mrs Palin appears on The Oprah Winfrey Show.

He will present a serious political problem for the former vice-presidential candidate unless she can stop him from accusing her of abandoning politics for money and calling one of her children retarded.

Mr Johnston, the father of Mrs Palin’s grandchild, has used an interview that was broadcast nationally to claim that he knows secrets that could damage her in unspecified ways but is holding them back because he does not want to hurt her.

Mrs Palin resigned as Governor of Alaska in July while still the subject of unresolved ethics complaints. Mr Johnston lived with the Palin family for about two months last year when he was dating Mrs Palin’s eldest daughter. The couple had a baby but then separated.

“I have things that . . . would get [Mrs Palin] in trouble and could hurt her, will hurt her,” he told CBS News in a two-part interview that concluded yesterday with a discussion of the merits of nude modelling. “If I really wanted to hurt her, I could, very easily,” he said. “But I’m not going to do it. I’m not going that far.”

The allegations made by Mr Johnston have already hurt Mrs Palin enough to elicit a furious response from her staff. When he repeated claims that she often referred to her youngest son, Trig, who has Down’s syndrome, as retarded, her office said: “We have purposefully ignored the mean-spirited, malicious and untrue attacks on our family . . . Trig is our ‘blessed little angel’, who knows it and is lovingly called that every day of his life.”

The Palin camp advised those following the saga to “consider the source” of its latest chapter, suggesting that Mr Johnston’s decision to bare all for a magazine reflected a “desperate need for attention”.

“I don’t think it should matter in her eyes what I’m doing,” the aspiring model said yesterday. “She’s doing her thing, I’m doing mine . . . She’s quitting Governor for her money so we’re kind of on the same page here.”

Technically speaking, that is not true. Mrs Palin has finished recently several hundred pages of prose billed as her side of the story of the election defeat last year, after which McCain campaign staff savaged her as a selfabsorbed prima donna.

Mr Johnston, meanwhile, will take off every stitch of clothing for a Playgirl centre spread. He was coy about the details on the CBS studio couch, but his manager confirmed yesterday that “everything’s going to hang out; we’re talking ‘full Johnston’.” For that perfect look, he has been working out in the gym for the past month.

Mr Johnston has shown some talent for self-parody in his short career as a celebrity, appearing in a television advertisement for pistachio nuts under the slogan: “Now Levi Johnston does it with protection” — a reference to the nuts’ shells, but also to his involvement in the most publicised teenage pregnancy in America in recent years.

There was not much evidence of self-awareness in his effort to spin his nude modelling debut in advance, however. “I don’t want to be looked at as someone who’s getting naked for fame and that kind of thing,” he said. “I think when people see it, it’s not going to be like what they think. It’s going to be good.”

Mr Johnston has been the sole provider for his sister since his mother was sentenced to jail earlier this year for selling prescription painkillers. He claims that the Palins have not allowed him to spend time alone with his son, and said yesterday: “I don’t see myself over there for Christmas.”

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