Lord Flowers: Physicist who did major work on atomic nuclei and became a respected administrator

Brian Flowers made his mark in physics and in science policy and administration.

I met him first in the late 1940s, when he was in charge of an experimental group at the Atomic Energy Research Establishment, Harwell. He had come from Swansea, where his father was a minister, had taken a wartime physics degree at Caius College, Cambridge, and had then been directed to do work in experimental nuclear physics at the Montreal Laboratory for Atomic Energy (which later moved to Chalk River). One noticed him at Harwell: he was evidently bright, full of energy, and very sociable.

His work was going well, but he felt that his heart was in theoretical work, and in 1950 he was seconded to the Mathematical Physics Department at Birmingham University (which I was directing) as a graduate student in theoretical physics. The handsome young man who turned up in Birmingham in a fast sports car was no ordinary student.

This was the time when the nuclear shell model was proving itself as a tool for gaining an understanding of atomic nuclei. Our thinking about nuclei had been dominated by the idea that the constituent particles inside a nucleus were interacting with each other very strongly, so that none could move far without being deflected by a collision with another. This picture came from Niels Bohr's successful treatment of the collisions of neutrons with nuclei, but was mistakenly believed to apply also to nuclei in or near their normal states. In the latter case, observations had forced us to accept the alternative picture of particles moving largely independently of each other, each pursuing its own orbit, with only occasional collisions.

Flowers took up this new approach with enthusiasm. He showed in particular how to base the use of this model on a quantitative picture of the states of real nuclei. In a short time he had become one of the acknowledged experts in the field and inspired the work of several junior collaborators. The university recognised his unusual record by awarding him, after two years, a DSc instead of the PhD he would have expected to claim.

On Flowers' return to Harwell, the director Sir John Cockcroft appointed him head of the Theoretical Physics Division. This was a bold step because Flowers had been in theoretical work for only two years, but his performance justified it. The division had been without a head since the arrest in 1950 of the spy Klaus Fuchs, a blow to the morale of the team; various interim arrangements had kept things going. Now Flowers succeeded in raising spirits. He also strengthened the team by attracting new people of excellence and helped them to develop. The division made many contributions to basic science as well as to the specific problems of atomic energy with which Harwell was concerned.

Almost simultaneously with taking up his responsibilities at Harwell he acquired new domestic responsibilities. In 1951 he married Mary, née Behrens, who had two sons from a previous marriage. The new parental role was carried lightly and successfully.

In 1958 he moved to the University of Manchester as professor of theoretical physics. He succeeded Léon Rosenfeld, who had built up a strong department there. After three years, Flowers found himself in charge of the whole of Manchester physics as Langworthy Professor, succeeding S Devons in a chair that had been held by Rutherford, WL Bragg and PM Blackett. He continued contributing imaginative ideas to nuclear physics, and guiding a research team, but much of his time now had to be spent on running a large, predominantly experimental department.

When he became chairman of the Science Research Council in 1967 it finally meant the end of his personal research. Instead, his main attention had to be given to questions of science policy, at a critical time. This was before the era of brutal cuts in science budgets, but the principles of the financial support of science were already being questioned. Much controversy was caused by the report of Lord Rothschild, which took the line that applied research should be controlled by the "consumer", i.e. the particular government department or industrial organisation concerned with the applications.

As the subjects covered by the SRC included applied work, the strict application of the Rothschild philosophy would have caused severe, and in many people's views, harmful changes to its operations. Flowers opposed such extreme changes and succeeded in preserving the basic structure of the Research Council. It would have been undesirable to have a change of chairman while these arguments were going on, and his term of office was therefore extended for one year beyond the normal five.

During his SRC period he had retained contact with Manchester, and the possibility of returning to research and teaching, but after a six-year break this would have been difficult. He had demonstrated his ability as an administrator, and this opened up new, attractive possibilities. He became Rector of Imperial College, and later vice-chancellor of the University of London.

In all these positions he showed great flexibility of mind and willingness to listen. But in the end he would not hesitate to back decisions which he saw were right, even if they were unpopular. His views were always based on a solid command of the relevant facts; he was untiring in doing his homework. This included writing out with great care the text of any talk he had to give, even to a small audience, a surprising trait in one so experienced in public speaking.

His qualities also caused him to be much in demand for many part-time duties. These included being chairman of the Royal Commission for the Environment, of the Computer Board and of the London University working party on medical and dental teaching resources. The latter, which led to recommendations for closing or merging departments, was particularly effective in making him enemies. He was made a life peer in 1979 and served on the Lords' Select Committee on Science and Technology from 1980. He was a founder member of the Social Democratic Party.

He will be remembered for his warm interest in all those with whom he came in contact. If any friend or even casual acquaintance was in trouble, Lord and Lady Flowers would not just express sympathy, but would go out of their way to give help or constructive advice, or at least comfort. With the official and social demands on their time, there was always time for friends and for those in trouble.

Brian Hilton Flowers, scientist and administrator: born Swansea 13 September 1924; chancellor, Manchester University 1994–2001; chairman, Nuffield Foundation 1987–98; Kt 1969; cr. Life Peer 1979; married 1951 Mary Behrens (two stepsons); died 25 June 2010.

Rudolf Peierls died in 1995.