John Gurdon’s school report on his abilities in science left little doubt. “It has been,” his teacher at Eton wrote, “a disastrous half.” Moreover, Gurdon’s hopes of a career in the field were “quite ridiculous”.

Sixty years on, Sir John Gurdon, fellow of the Royal Society, has received an equally unambiguous but wholly different report. The 79-year-old has, it was explained, “revolutionised our understanding of how cells and organisms develop”. The authors of the latest report were even more distinguished than an Etonian master: they were the Nobel Prize Committee.

In 1962, having ignored his teacher’s advice, John Gurdon was a graduate student in zoology at Oxford. There, he performed an experiment transferring the nucleus of a mature frog’s intestinal cell into a frog’s egg. The resulting frogspawn shocked the biological community by becoming a fully functioning frog, overturning conventional dogma about cell development.

Yesterday, more than half a century after the schoolmaster told him that he would never be a successful scientist, this research was recognised when the Cambridge biologist won the Nobel Prize in Physiology or Medicine.

Sir John’s work showed that although the body’s cells can specialise in remarkably diverse ways, producing skin, lungs, muscles and intestines, they all retain the full genetic information to produce all other cells. So important was this discovery that the scientific community describe him as the godfather of both cloning and stem-cell therapy.

But he nearly did not become a scientist at all. After only a term, he came “bottom of the bottom form”. “Gurdon has ideas about becoming a scientist. On present showing, this is quite ridiculous,” wrote Mr Gaddum, the teacher whose name Sir John still remembers. He then went on to describe the future Nobel laureate as being unable to “learn simple biological facts”, arguing that continuing to teach him “would be a sheer waste of time both on his part and of those who have to teach him”.

Yesterday the Nobel committee begged to differ. Sir John, who was knighted in 1995, shares the award with Professor Shinya Yamanaka from Japan. The pair were praised for their discovery in separate work, “that mature, specialised cells can be reprogrammed to become immature cells capable of developing into all tissues of the body”. Professor Yamanaka built on Sir John’s work by showing in 2006 that by introducing only a few genes intact mature cells in mice could be reprogrammed to become stem cells.

Sir John, who now has a Cambridge research institute named after him and is a fellow of Churchill College, could have taken a different path. So disheartened was he by his school science experiences that when he applied to the University of Oxford it was to become a classicist. “The admissions tutor got in touch with me and said, ‘I’m delighted to tell you that we can accept you — on two conditions. One is that you start immediately. The second is that you do not study the subject in which you took the entrance exam’.”

Later, his work on the South African frog Xenopus showed that mature cells did not lose their irrelevant genetic information after specialising. “It was controversial,” said Sir John. “There was some preceding work that had come out with the opposite conclusion. I was in the position of taking a view as a graduate student that was not held by people much more senior to myself.”

The consequences of his work have been the application of similar tech- niques in the cloning of mammals such as Dolly the sheep. However, when the call came from the Nobel committee in Stockholm, Sir John was not sure whether to believe it. “It could be someone trying to trick you and put on a Swedish accent,” he said.

Now he has confirmed that the call was indeed genuine, one might think it time to forget the school report. But he disagrees. In fact, he has it framed in his office at the Gurdon Institute at Cambridge. “When you have problems like an experiment doesn’t work, it’s nice to remind yourself that perhaps after all you are not so good at this job. The schoolmaster may have been right,” he said.