Rosalind Franklin, the young British scientist whose experiments at King's College London were essential to the discovery of the double helix of DNA by James Watson and Francis Crick in 1953, was cheated of deserved recognition in part by her early death from cancer in 1958. Nobel prizes are never awarded posthumously. When Watson, Crick and Wilkins got their awards in 1962, she was therefore ineligible. But she had passed the hardest test that faces any humanist: the deathbed test. Franklin was born in London in 1920 to a distinguished Anglo-Jewish family. The first of their English line arrived as Fraenkel from Breslau in Silesia in 1763 and anglicised the name to Franklin.

Rosalind's family were not overly religious. Her formidable father, Ellis Franklin, was contemptuous of the over-literal Jewish orthodoxy which had forced his elderly father to be pushed in his bath chair and his elderly mother to struggle on foot to his eldest son's bar mitzvah in 1933 in order to avoid driving on a Saturday. But he expected his children to follow the rituals of their faith, and its obligations, chief among which was not to 'marry out'.

Rosalind, perhaps because of such constraints, never married. When she went up to Cambridge in 1938, she joined the Jewish Society to please her grandfather, but disliked it. She was passionately secular. She threw herself into science - physics, chemistry and crystallography. When, with the onset of war, it seemed as if Cambridge might close down, she thought she might get work as a chemist. Her patriotic father suggested some form of 'land work' but she rejected it out of hand. She would be 'quite exceptionally bad' at anything except science.

This flat declaration prompted Ellis Franklin to accuse his strong-willed daughter of making science her religion. He was right. Rosalind sent him a four-page declaration, eloquent for a young woman just over 20 let alone a scientist of any age.

"You frequently state, and in your letter you imply, that I have developed a completely one-sided outlook, and look at everything and think of everything in terms of science. Obviously my method of thought and reasoning is influenced by a scientific training - if that were not so my scientific training will have been a waste and a failure. But you look at science (or at least talk of it) as some sort of demoralising invention of man, something apart from real life, and which must be cautiously guarded and kept separate from everyday existence. But science and everyday life cannot and should not be separated. Science for me, gives a partial explanation of life. In so far as it goes, it is based on fact, experience and experiment. Your theories are those which you and many other people find easiest and pleasantest to believe, but so far as I can see, they have no foundation other than they lead to a pleasanter view of life (and an exaggerated idea of our own importance)…

"I agree that faith is essential to success in life (success of any sort) but I do not accept your definition of faith, i.e. belief in life after death. In my view, all that is necessary for faith is the belief that by doing our best we shall come nearer to success and that success in our aims (the improvement of the lot of mankind, present and future) is worth attaining. Anyone able to believe in all that religion implies obviously must have such faith, but I maintain that faith in this world is perfectly possible without faith in another world…

"It has just occurred to me that you may raise the question of a creator. A creator of what? […] I see no reason to believe that a creator of protoplasm or primeval matter, if such there be, has any reason to be interested in our insignificant race in a tiny corner of the universe, and still less in us, as still more insignificant individuals. Again, I see no reason why the belief that we are insignificant or fortuitous should lessen our faith - as I have defined it."

If she were making science her religion, Rosalind chose wisely, for it served her well. After taking her degree in physical chemistry from Cambridge, she went to work - and even her father could not deny it was 'war work' - at the British Coal Utilisation Research Board in Kingston, outside London. There she did research on the structure of coal that resulted in papers still recognised as classics today.

A lucky break took her to Paris in 1947 where she worked as a physical chemist on the analysis of awkward crystals. She enjoyed the unisex camaraderie of the laboratory and the disputatious lunches at the Café Solange on the Left Bank, and began making an international reputation. In March 1950, however, thinking she should perhaps return to the mainstream of British science, she applied for, and won, a fellowship to work at King's College London. Unenthusiastic, she wrote to her brother: "I spend half my time wondering whether to chuck the whole thing up and stay here."

But moving, like the focus of twentieth-century science itself, from physics into biology was the right decision. At King's she soon found herself working on the x-ray analysis of the structure of the molecule DNA, only recently identified as 'the molecule of life', the genetic messenger carrying information on replication from old cells to new.

She hated King's on sight. Ecclesiastical and non-Oxbridge in atmosphere, she felt she had made a mistake. Worse, she disliked intensely the man who should have been her closest colleague, Maurice Wilkins. Consequently, she ignored him, and, with the aid of her research assistant, soon had remarkable results. The only researcher working at high humidity, she took sharp clear pictures that revealed what no one had noticed before: there were two forms of DNA, and previous attempts to map the structure had muddled the two. She also worked out, with the X-ray photographs she was singularly gifted at taking, the dimensions of the unit cell - the basic building block - of DNA.

Wilkins, feeling shut out of his subject, went frequently to Cambridge and talked with his old friend Francis Crick. Nearby was the young American, James Watson, listening eagerly. Watson and Crick were determined to try to build a conjectural model of the structure of DNA. With what they gleaned from Wilkins about Rosalind's data, and also from an internal report they wrangled a look at, they pooled their imaginations and came up with the model of the double helix that - as they announced in the pub early in March 1953 - proclaimed the secret of life. That is, the secret of how cells copy each other from old to new.

Rosalind never knew they had seen her photographs or her data. And to her dying day she never knew Watson and Crick would be proclaiming from platforms half a century later that they could not have cracked the structure of DNA in March 1953 without her data.

So unhappy was she at ecclesiastical King's that she organised the transfer of her fellowship to secular Birkbeck College in March 1953. There she produced 17 excellent papers on viruses before being struck, in August 1956, with ovarian cancer.

And true to her own her personal faith in science, when the cancer that first struck in 1956 recurred, Rosalind asked her surgeon for an honest prognosis. He was frank and discouraging. He urged her to seek the comforts of religion and be grateful that she had time to prepare her soul.

She was furious - with him, for despairing, and with science, for not having discovered a way to halt the progress of her disease until a cure could be found. She remained hopeful until the end that each new treatment, such as cobalt radiotherapy, might be the answer. Until three weeks before her death, she went into her lab at Birkbeck College almost every day.

When she entered the Royal Marsden Hospital in late March 1958, she kept an invitation to a fellowship in Caracas on her bedside. She spoke eagerly of her model of a virus that was to be exhibited at the forthcoming Brussels World's Fair. The fair opened just as she died, on April 16, 1958.

Her gravestone in the Franklin family plot in the United Jewish Cemetery in Willesden respects her secularity. Those of her grandparents proclaim: "This stone was obtained from the Holy Land." Rosalind's says, "Scientist: her work on viruses was of lasting benefit to mankind."

With the dramatic progress of genetic medicine, this wording perhaps should be altered to reflect her DNA contributions. However, the words of her obituarist in Nature, the crystallographer J.D. Bernal, wrote: "As a scientist, Miss Franklin was distinguished by extreme clarity and perfection in everything she undertook. Her photographs are among the most beautiful X-ray photographs of any substance ever taken."

"Clarity and perfection" would surely meet Rosalind's stern definition of faith: "The belief that by doing our best we shall come nearer to success and that success in our aims (the improvement of the lot of mankind, present and future) is worth attaining."