In Britain and Atomic Energy 1939-1945 (1964) and its two-volume sequel, Independence and Deterrence (1974, written with the assistance of her friend and collaborator Lorna Arnold), she offered a characteristically clear-eyed account of the fashioning and implementation of British policy with regard to atomic energy from the outbreak of the war until October 1952, when "Hurricane" - the test of a rather primitive bomb at Monte Bello, a group of islands off the north-west coast of Australia - propelled Britain to the status of the world's third nuclear power.
These books, along with her many articles, major public lectures, and penetrating reviews, established her not merely as a peerless chronicler and analyst of a crucial facet of the war effort and of Britain's subsequent struggles to maintain great power status, but also as a leading commentator on the relations between science and government. Her election first to the British Academy in 1975 and 13 years later to the Royal Society recognised equally the quality and the breadth of her work and placed her, with Sir Karl Popper and Joseph Needham, among the tiny handful of those who have been Fellows of both bodies.
Important methodological foundations for Gowing's work were laid in the 14 years that she spent in the historical section of the Cabinet Office from 1945. But the two books she published in these years - The British War Economy (1949, written with Sir Keith Hancock) and Civil Industry and Trade (1952, with Eric Hargreaves) - gave little indication of the turn that her career was to take once she joined the United Kingdom Atomic Energy Authority as historian and archivist in 1959.
With unfettered access to both records and many of the scientists and policy-makers who had helped to fashion the history to which she now turned her hand, she demonstrated that official history could meet the most exacting academic standards. Winning the confidence of civil servants, politicians, and (despite her lack of any previous training in science) the scientific community, she traced unerringly the rivalries, resentments, and suspicions that lay behind domestic party politics and the facade of cooperative Anglo-American endeavour, a facade that creaked and then, with the war over, cracked irretrievably under the strain of the widening technological gap between manifestly unequal powers.
To a degree unmatched by any historian before or since, she made sense of the resolve, shared by the administrations of both Clement Attlee and Winston Churchill and seriously challenged at the time only by Patrick Blackett, that Britain should have her own atomic bomb.
In 1966 Gowing moved into academic life, as Reader in Contemporary History at the University of Kent. Her time there was clouded by the death of her husband, Donald, after a long illness and 25 years of marriage, and by disagreements within the university that culminated in her decision to apply for Oxford University's newly created Chair of the History of Science in the spring of 1972. As a candidate coming from outside the main stream of the history of science, she had little expectation of even being shortlisted, but she was appointed, and in January 1973 she took up the chair and the associated fellowship at Linacre College.
Her appointment was not uncontroversial, and feelings in certain quarters never entirely subsided. Gowing, though, was uncompromising in her vision of a history of science rooted squarely in the detailed examination of the social, political, and economic context of science and technology. While her vision accommodated the treatment of scientific thought, it had no room for what she perceived as an undue preoccupation with the abstract filiation of ideas, and although her relations with philosophers remained good, she welcomed moves to weaken the formal ties that, in Oxford as in many other universities, had bound the history of science to the philosophy of science.
In her memorable inaugural lecture, What's Science to History or History to Science? (1975), Gowing delivered a characteristic protest against the "man-made frontiers" that set science apart from history. Yet her involvement in the day-to-day life of the Modern History faculty, in which she held her chair but in which she found little scope for teaching her speciality, was never close. She found the scientists whose world she studied more receptive to her conception of the proper place of science and technology on the agenda of the contemporary historian, and it was entirely consistent with this conception and with her respect for the scientific enterprise that, immediately after taking up her chair, she assumed a leading role, with the physicist Nicholas Kurti, in the establishment of the Contemporary Scientific Archives Centre, now relocated at Bath University.
Here, in her 13 years as professor and honorary director of the centre, well over a hundred collections of the papers of 20th-century scientists were catalogued and then deposited in suitable locations. The same concern about the lack of recognition for science to which this initiative was a response also fired her work for the Lord Chancellor's Advisory Council on Public Records, the BBC Archives Advisory Committee, and (a world that she particularly enjoyed) the National Portrait Gallery, where, as a Trustee from 1978 to 1992, she argued a relentless case for the acquisition of more portraits of scientists and engineers.
Gowing was a socialist whose far from comfortable early life left her with a keen sense of human injustice and folly. Born Margaret Elliott, the youngest of three children, in North Kensington, she took full advantage of the experiences that London offered a poor child, and it was her memory of the benefits of free entry to national museums that fired her anger at the introduction of charges at the Imperial War Museum (from whose Board of Trustees she consequently resigned) and the Science Museum in the 1980s.
From her elementary school, she went in 1932 to Christ's Hospital in Hertford, with the aid of a London County Council scholarship, and in 1938, again supported by scholarships, she entered the London School of Economics. The First in Economic History that she took in 1941 led on to appointments in the Ministry of Supply and the Board of Trade and in due course her move to the Cabinet Office in 1945.
The world of administration suited her well, and with her unswerving belief in the merits of enlightened central government, she would certainly have risen even higher than she did in the Civil Service, had her contact with Keith Hancock, who made her his assistant in the Cabinet Office's project for a series of civil histories of the war, not set her on the very different path that her career was subsequently to take.
Gowing was not by nature a compromiser, and her convictions were held with a tenacity that showed equally in her dislikes, not least of the policies of Margaret Thatcher's governments, and in her attachments to both people and principles. She was devoted to her two sons, Nicholas and James, fiercely loyal in her friendships (not least with a number of younger scholars to whom she lent unstinting support), and generous in her appreciation of those (Hancock, George Allen, Richard Titmuss, Christopher Hinton, and Rudolf Peierls among them) who won her respect.
Of the institutions she graced, none retained her affection more than her Oxford college, Linacre. There she enjoyed the informality of a common room in which her warmth was reciprocated and in which contacts with a fellowship that included some of the university's most eminent scientists made a signal contribution to her work.
Members of the college shared her pleasure at the recognition that came in such abundance in her Oxford years, including honorary doctorates from the universities of Leeds, Leicester, Manchester, and Bath, a Festschrift (Science, Politics and the Public Good, 1988, edited by Nicolaas Rupke), and her appointment as CBE in 1991. They were also among those who felt the pain of her last years most keenly, as Alzheimer's disease, to her all too manifest distress, gradually undermined her capacity for work. Margaret Mary Elliott, historian of science: born London 26 April 1921; Historian and Archivist, UK Atomic Energy Authority 1959-66; Reader in Contemporary History, University of Kent 1966-72; Professor of the History of Science, Oxford University 1973- 86; Fellow of Linacre College 1973-86; FBA 1975; FRS 1988; CBE 1991; married 1944 Donald Gowing (died 1969; two sons); died London 7 November 1998.