The News of the World spiked an exclusive story exposing the science fiction writer Arthur C Clarke as a paedophile, according to a new book about life inside the newspaper whose closure was announced a year ago today.

In Hack, an account of his nerve-shredding days as a reporter on the News of the World and then the Sunday Mirror, Graham Johnson claims that although the NOTW prided itself on outing pederasts, editors made an exception for Mr Clarke because he was a friend of Rupert Murdoch.

Through BSkyB, the tycoon commercially exploited the futurologist's theory that satellites would be ideal for communications and praised him in public. As a result, according to Mr Johnson, who by that time had been sacked by the NOTW and had joined the Sunday Mirror, a story by reporter Roger Insall about Mr Clarke's alleged abuse of adolescent boys was never published for fear of upsetting the proprietor.

Tipped off about the story, the Sunday Mirror sent Mr Johnson to Colombo, where he extracted an confession from the author that he paid boys for sex. "I have never had the slightest interest in children – boys or girls. They should be treated in the same way. But once they have reached the age of puberty, then it is OK," Mr Clarke was quoted as saying in the Sunday Mirror. "If the kids enjoy it and don't mind it doesn't do any harm … there is a hysteria about the whole thing in the West."

Mr Clarke subsequently denied he was a paedophile, saying: "The allegations are wholly denied." But he never sued the Sunday Mirror and died aged 90 at his Sri Lanka home in 2008.

Speaking to The Independent yesterday, Mr Johnson said: "Roger [Insall] said that because Arthur C Clarke was a mate of Rupert Murdoch, the editor wasn't having any of it and despite Roger getting a lot of evidence that Clarke was a paedophile they wouldn't publish it."

Yesterday, Phil Hall, the then editor, said: "I can vaguely remember that story. I do remember that Roger Insall worked on it and I remember it was not published. My only recollection is that the only reason we wouldn't publish it was because of legal reasons."