I have just had a great triumph, though a somewhat disagreeable one. I and a few others decided it was time something was done about the . . . going out to the trenches ... for every warning - we have had only one quite undisturbed night - yesterday the thing went at 7.30 and lasted until 11.15. I had to do some work. We were the only college being handicapped in this way - and I was getting badly behind. So three of us stayed in on the first floor and boldly left the light showing through the door. Mrs. Palmer came in in a storm and turned us out, saying we were 'disloyal, deceitful and untrustworthy' and were to see her today. Before we saw her she had called a meeting to say that nobody need go to the trenches before 11 PM!

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.

For myself, Birkbeck is an improvement on King's, as it couldn't fail to be. But the disadvantages of Bernal's group are obvious - a lot of narrow-mindedness, and obstruction directed especially at those who are not Party members. It's been very slow starting up there, but I still think it might work out all right in the end. I'm starting X-ray work on viruses (the old TMV to begin with) and I'm also to have somebody paid by the Coal Board to work under me on coal problems more or less the continuation of what I was doing in Paris. But so far I've failed to find a suitable person for the job.

There is no doubt that she could be a difficult character - impatient, bossy, intransigent. She always went straight to the point and was seldom diplomatic. However, this was all because she had such high standards and expected everyone else to be able to reach her ideal requirements.

She discovered in a series of beautifully executed researches, the fundamental distinction between carbons that turned on heating into graphite and those that did not. Further, she related the difference to the chemical constitution of the molecules from which the carbon was made. She was already a recognised authority in industrial physicochemistry when she chose to abandon this work in favour of the far more difficult and more exciting fields of biophysics.

By the most ingenious experimental and mathematical techniques of X-ray analysis, she was able to verify and make more precise the illuminating hypothesis of Crick and Watson on the double spiral structure of this substance. She established definitely that the main sugar phosphate chain of nucleic acid lay on an outside spiral and not on an inner one, as had been authoritatively suggested.

In this close collaboration between the Cambridge and London schools it is difficult to disentangle all the contributions of individuals, but what Miss Franklin had to give was the technique of preparing and taking X-ray photographs of the two hydrated forms of deoxyribonucleic acid and by applying the methods of Patterson function analysis to show that the structure was best accounted for by a double spiral of nucleotides, in which the phosphorus atoms lay on the outside.

Though her (Rosalind Franklin) features were strong, she was not unattractive and might have been quite stunning had she taken even a mild interest in clothes. This she did not. There was never lipstick to contrast with her straight black hair, while at the age of thirty-one her dresses showed all the imagination of English blue-stocking adolescents.

A decisive breakthrough in human thought is not necessarily the work of an individual genius but only of a pack of bright and well-financed research workers following a good well-laid trail.

For 'Rosy', in the book - I had come to know and respect her and to admire her too, as a very intelligent and brave woman who was the first to recognise and to measure the phosphorus atoms in the helix, which proves to be the outer one, thus showing Pauling to be wrong and the helix to be a double one, though this inference is not drawn.

The forgotten heroine of the race to unravel the mystery of human DNA is to be honoured posthumously as part of a Government crusade against sexism in science.

Rosalind Franklin has become a feminist cause célèbre , the dedicated scientist held back by her male colleagues' refusal to acknowledge her vital role in one of the most important scientific discoveries of the century.

While the three male scientists who helped establish the double-helix structure of DNA shared the Nobel prize for their breakthrough - based in large part on Franklin's detailed X-ray images of atoms - she won little public recognition and her early death robbed her of later fame.

'Rosy' was dismissed in James Watson's account of the discovery, The Double Helix, as a buttoned-up bluestocking who, her scientific partner believed, 'had to go, or be put in her place'. Only recently has her reputation begun to be restored.

Now Patricia Hewitt, the Trade and Industry Secretary, is to create a Franklin Medal in her honour to raise the profile of other women scientists, with a £30,000 annual prize for exceptional innovation.

In 1975, a biography was published of a woman scientist who had died from cancer at 37. In the research community of crystallographers, Rosalind Franklin had been highly regarded for her ability to produce X-ray photographs with exquisite precision, but in the wider world she was unknown. Her friend Anne Sayre changed this, for her biography, Rosalind Franklin and DNA, demonstrated to a huge readership that Franklin's work was crucial to establishing the structure of DNA.

The immediate provocation was James Watson's hugely popular book, The Double Helix (1968). It was not just that Watson systematically stereotyped Franklin, making her out to be a bluestocking and a frump, nor that he called her "Rosy" when even to her intimates she was Rosalind, but that this stereotyping enabled him to erase Franklin's crucial contribution of the X-ray photographs that confirmed the helical structure.

Written with the support of many crystallographers outraged by Watson's unprofessional treatment of a colleague, above all one silenced cruelly by premature death, Sayre's biography spoke directly to the rising women's movement. Its subtitle, "A vivid view of what it is like to be a gifted woman in an especially male profession", made sure of that.

The bones of the argument are these: the Cambridge-based DNA model-builders, Francis Crick and James Watson, needed the collaboration of the King's London-based experimentalists, Maurice Wilkins and Rosalind Franklin, because only experimentalists could provide the crucial X-ray evidence of the helical structure. Unguardedly, Wilkins showed Franklin's photos to Crick and Watson without her permission. Max Perutz, another Cambridge-based scientist, also passed the model-builders a confidential report, including Franklin's detailed notes and X-ray photographs, which he had received as part of his Medical Research Council duties evaluating the King's unit.

Rosalind Franklin remained virtually unknown outside her immediate circles until 1968 when Watson published The Double Helix, his brilliant, tactless and exciting personal account of the discovery. In it, she is the terrible Rosy, the bad-tempered bluestocking who hoarded her data and might have been pretty if she had taken off her glasses and done something interesting with her hair.

She looked quite different to the eminent physics professor J.D. Bernal, who brought her to Birkbeck in the spring and oversaw her five happy and productive years there. He described her in Nature: '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.'

But Bernal's words were elegiac. Rosalind Franklin's life was cut short by ovarian cancer in 1958 when she was thirty-seven - four years before Watson, Crick and Wilkins won the Nobel prize for their DNA discovery and a decade before she was caricatured in a book to which, alone of the principals portrayed, she was unable to answer back.

In March 1953 Maurice Wilkins of King's College London announced the departure of his obstructive colleague, Rosalind Franklin to rival Cavendish Laboratory scientist, Francis Crick. But it was too late. Franklin's unpublished data and crucial photograph of DNA had already been seen by her competitors at the Cambridge University lab. With the aid of these, plus their own knowledge, Watson and Crick discovered the structure of the molecule that genes are composed of - DNA, the secret of life. Five years later, and more brilliant research under Bernal at Birkbeck College, at the age of thirty-seven, Risalind died of ovarian cancer. In 1962 Wilkins, Crick and Watson were awarded the Nobel prize for their elucidation of DNA's structure. Franklin's part was forgotten until she was caricatured in Watson's book The Double Helix. In this full and balanced biography Brenda Maddox has been given unique access to Rosalind's personal correspondence and has interviewed all the principal scientists involved, including Crick, Watson and Wilkins. (Brenda Maddox, Harper Collins, ISBN 0 00 257149 8)