A mountaineer-philanthropist who shot into the best-seller lists with a book detailing his efforts to build girls’ schools in remote villages of Pakistan and Afghanistan fudged many of the facts in his heart-swelling story and has exaggerated the extent of his charity work, claims a documentary by CBS News to be broadcast in the US tonight.

A reporter for the 60 Minutes current affairs magazine will claim that pages of the inspirational book ‘Three Cups of Tea’, published in 2006 by Penguin, are threaded through with distortions, and that its author, Greg Mortenson, has claimed credit for some schools that appear either to have been built by someone else entirely or don't exist at all.

Mortenson (53) whose Central Asia Institute (CAI) has claimed to have provided schooling for 60,000 girls in the region, is this weekend countering charges that include questions over the probity of his financial relationship with the charity. He suggests that those making the charges are doing so for television ratings. “I hope these attacks, the people doing these things, know this could be devastating for tens of thousands of girls,” a clearly stung Mortenson told the Bozeman Daily Chronicle - his local newspaper in Montana.

After selling only conservative numbers in hardback, ‘Three Cups of Tea’ took off when it went into paperback, selling more than three million copies worldwide and providing an unexpected boon for Mortenson, the institute, and Penguin. CBS also questions whether money raised by the CAI ostensibly for new schools may have gone to promoting the book, including private jet travel for Mortenson. The suggestion that the book is not quite the strict memoir it purports to be will distress many of Mortenson's myriad fans. Arguably, the most compelling section of the book - that he stumbled on the village of Korphe, where his mission to build schools began, after becoming lost while attempting an ascent of K2, the Himalayan mountain - is seemingly also one of its most fanciful.

The CBS segment cites local porters on the expedition with Mortenson saying his first encounter with Korphe and subsequent love affair with its inhabitants never happened, or at least not on that trip. Among those casting doubt on Mortenson in the CBS exposé is Jon Krakauer, a fellow writer-adventurer whose biggest book is ‘Into Thin Air’. He says he had also heard stories suggesting Mortenson's version of being taken in by the people of Korphe was essentially made up. It was “a beautiful story” but also “a lie”, Krakauer asserts.

Also questioned by CBS is a story of being kidnapped in 1996 by Taliban fighters. Contacted by CBS, one fighter said they did no such thing. The writer's version was “totally false”, and had been made up “to sell his book”.

Mortenson has claimed his CAI has been responsible for the building of 173 schools in the two countries and, with its newfound fundraising prowess - the institute raised $23.7 million just last year - is in a position to build another 63 schools a year. He said in a statement: “I stand by the information in my book and by the value of CAI's work in empowering local communities to build and operate schools that have educated more than 60,000 students.”

However, in his Chronicle interview, Mortenson appears to concede that he had conflated reality about when and how he first visited Korphe, suggesting it didn't happen during the K2 expedition. He said he and his co-author agreed at times to “simplify the sequence of events for the purposes of telling what was, at times, a complicated story”.

— By arrangement with The Independent