The fact was covered up by the then British ambassador to Nepal, Christopher Summerhayes, and John Hunt, leader of the expedition, the book based on archival material claims.
The book, by British author Mick Conefrey, is titled 'Everest 1953: The Epic Story of the First Ascent' to be released next month. Summerhayes and Hunt allegedly doctored the official account to conceal who got to the peak first, and decided to share the credit with Norgay to defuse growing anti-colonial feelings at the time in India and Nepal, The Sunday Times reported today.
The cover-up by Summerhayes and Hunt was reportedly exposed by the discovery of a memo in the archives of the Royal Geographical Society. The archives included the original account of the achievement by Hillary. His account, contained in a three-page memo, states clearly that he was the first to reach the summit: "(I) stepped on top of Everest... I quickly brought up Tensing (sic) beside me".
The memo reportedly states that Hunt insisted on the revised version "due to a desire not to cause offence to Nepalese nationalists and smooth over the dispute as to who got there first".
But the version made public by the expedition in Kathmandu, the wording was ambiguous, as it stated: "A few more whacks of the ice axe in the firm snow and we stood on the summit".
The Sunday Times reported: "By the time the version was released the issue had already escalated into a political row, with the press in Nepal and India lionising Tenzing as a means of whipping up post-colonial antagonism against Britain".
On the decision of the British authorities to offer Tenzing a George medal rather than the knighthood granted to Hillary, Conefrey writes that the real reason was because India had claimed Tenzing as one of its citizens.
After independence in 1947 its constitution explicitly stated that no citizen could accept any title from a foreign state, the report said. Hillary died in 2008, aged 88, while Norgay died in 1986 aged 71.