Consistently rated as one of the greatest books written about science in the past century, it has been hailed as a work that combines the plot line of a racy novel with deep insights about the nature of modern research.

But James Watson, author of The Double Helix, has revealed that his masterpiece came close to being suppressed. In an exclusive interview with the Observer, he admitted last week that his account of the discovery of the structure of DNA, when shown to friends and colleagues in the late 60s, triggered such hostility and outrage it seemed fated never to appear in print.

"You have grossly invaded my privacy," complained his close colleague, Francis Crick. Another collaborator, Maurice Wilkins, objected that the book presents "a distorted and unfavourable image of scientists". Given that Crick and Wilkins were the men with whom Watson had shared the Nobel prize for physiology in 1962 for their work on uncovering DNA's structure, the opposition of the two British researchers to the words of the young American scientist were worrying.

Many publishers were frightened off by threats of legal action from the manuscript's critics. Watson's depictions of several scientists were deeply unflattering and the book's secondary plot, which focuses on Watson's pursuit of young women – or "popsies" as he called them – around Cambridge, was considered irrelevant and patronising. Harvard University Press, having accepted Watson's manuscript for publication, came under pressure from the university's senior administrators and dropped the book.

It took the intervention of Lady Alice Bragg, the wife of Watson's former boss, Sir [William] Lawrence Bragg, to save The Double Helix, Watson has revealed. Bragg was head of the Cavendish laboratory in Cambridge where Watson had worked with Crick on the structure of DNA in the 1950s and was part of the British establishment.

"I needed to have Bragg on my side," Watson explained to the Observer last week. "So I suggested he write the foreword to my book. That would make it look acceptable to the establishment and to most of my critics. It took me a while to screw up my courage to write to him to ask for a foreword, but I did in the end."

Bragg – whom Watson once likened to Colonel Blimp – was initially infuriated by Watson's impudence and by The Double Helix's mixture of gossip and insulting caricatures of senior scientists. However, he was persuaded by Lady Bragg, who had enjoyed the book, to change his mind and in the end he agreed to write a foreword for it, describing The Double Helix as a "drama of the highest order; the tension mounts and mounts towards the final climax". His endorsement – or more precisely Lady Bragg's intervention – saved the day, we now know. The Double Helix was published in 1968 and became a worldwide bestseller.

With hindsight, the book's success is scarcely surprising. Watson's story, characterised by scientific opportunism, brashness and brilliant deduction, is a fascinating yarn. It is also one of considerable importance. In showing that the structure of DNA, the substance from which our genes are made, was that of a double helix, Crick and Watson had explained the mechanism underpinning the inheritance of biological characteristics and had made a breakthrough of immense scientific importance. The whole field of genomics, the creation of DNA fingerprinting and the development of the science of synthetic biology would have been impossible without Crick and Watson's breakthrough in Cambridge in 1953.

It is estimated today that The Double Helix has sold more than a million copies over the past 45 years. A TV dramatisation was also made in 1987 starring Jeff Goldblum as Watson, Tim Pigott-Smith as Crick and Alan Howard as Wilkins. And now a special annotated and illustrated version of The Double Helix has been published to mark the 50th anniversary of Watson, Crick and Wilkins winning their Nobel prize. The book, edited by Alexander Gann and Jan Witkowski, contains a mass of new material, including a series of letters written by Crick, that were only recently discovered and which reveal in detail the scientist's mounting fury about a book he claimed was "a violation of friendship" and which he described as being more "a fragment of your autobiography" than a history of the discovery of DNA's structure. (In the end, Crick – who died in 2004 – changed his mind and accepted the book's merits, and he and Watson remained friends.)

In addition, a chapter excised from the first edition has been restored, together with contemporary reviews of the book, most of which are favourable, though a few are hostile.

The new version also includes a letter from the writer Naomi Mitchison – whose son Avrion was a close friend of Watson – in which she describes the book "as if it were my child". Watson had written most of The Double Helix while staying at Carradale, the Mitchison house on the Mull of Kintyre, and dedicated the book to Naomi. "Perhaps, you will never write this sort of thing again, that doesn't matter, you've done it once and for all," Mitchison added in her letter.

These were prophetic words. Watson – who is now 84 – has never come close to repeating the success of The Double Helix, though he has published several other books. On the other hand, he has remained at the centre of the public stage as a champion of science, often with controversial results. In 2007, after making remarks about racial differences in intelligence between Africans and others, he was forced to retire as chancellor of the Cold Spring Harbor Laboratory in New York.

Watson has denied strenuously since then that he is a racist. His remarks were merely ill-considered, he has argued. To judge from the pages of The Double Helix, this habit – of speaking first, and thinking later – is not a new one. Apart from his attitude to "popsies" and disdain for many of his colleagues, Watson's treatment of Wilkins and his colleague Rosalind Franklin has come in for criticism over the years. Wilkins and Franklin (who died of cancer in 1958) were studying DNA at King's College London. Crick and Watson were based in Cambridge but never carried out an experiment of their own. Instead they exploited some of Franklin and Wilkins' X-ray crystallography research to work out the structure of DNA. At the same time Watson portrays Franklin in a cold, unfriendly manner.

But Watson last week insisted there was no animosity. "We never felt we were doing anything bad to her," he told the Observer. Franklin, with Wilkins, wanted to get their data first and then work out the structure of DNA. "We wanted to be ahead of the data." While Franklin and Wilkins continued with their X-ray work, Crick and Watson worked on different models of the DNA molecule until they hit the right one, a double helix.

If fact, if there was a tragic figure in the story of DNA it was Maurice Wilkins, Watson insisted. Of the four scientists working on DNA – two at Cambridge and two in London – in 1953, he was the only one who had been researching its structure for any length of time. Franklin was imposed on him by the head of his laboratory, John Randall, who emerges from the pages of The Double Helix as a rather Machiavellian figure. In the end, Franklin and Wilkins hardly spoke to each other and Crick and Watson stole the glory while they sulked.

The book also reveals that at the time MI5 was opening Wilkins's mail on the supposition that he was a communist spy. "He wasn't," says Watson. "He was just a rather tragic individual. It was a great shame."

• This article was amended on 13 December 2012 to correctly identify Sir William Lawrence Bragg.

■ The Annotated and Illustrated Double Helix, by James Watson, edited by Alexander Gann and Jan Witkowski, is published by Simon & Schuster