Professor Sir Joseph Rotblat was one of the most distinguished scientists and peace campaigners of the post second world war period. He made significant contributions to nuclear physics and worked on the development of the atomic bomb. He then became one of the world’s leading researchers into the biological effects of radiation. His life from the early 1950s until his death in August 2005 was devoted to the abolition of nuclear weapons and peace. For this he was awarded the Nobel Peace Prize in 1995. His work in this area ranked with that of Albert Einstein and Bertrand Russell and this article is an attempt to summarise his life, achievements and outline his views on the moral responsibilities of the scientist. He is a towering intellectual figure and his contributions to mankind should be better known and more widely understood.

Early life and times in Poland Joseph Rotblat was born to a Jewish family in Warsaw, Poland on November 4 1908 one of seven children (two not surviving child birth). His father, Zygmunt built up and ran a nationwide horse drawn carriage business, owned land and bred horses. His early years were spent in what was a prosperous household but circumstances changed at the outbreak of the First World War. Borders were closed and horses requisitioned leading to the failure of the business and poverty. After the end of the War he worked as a domestic electrician in Warsaw and had a growing ambition to become a physicist. Without formal education he won a place in the physics department of the Free University of Poland gaining an MA in 1932 and Doctor of Physics, University of Warsaw, 1938. He held the position of Research Fellow in the Radiation Laboratory of the Scientific Society of Warsaw and became assistant Director of the Atomic Physics Institute of the Free University of Poland in 1937. During this period he married a literature student, Tola Gryn. Before the outbreak of war, he had conducted experiments which showed that in the fission process neutrons were emitted. In early 1939 he envisaged that a large number of fissions could occur and if this happened within a sufficiently short period of time then

considerable amounts of energy could be released. He went on to calculate that this process could occur in less than a microsecond and as a consequence would result in an explosion. The idea of an atomic bomb occurred to him in February 1939 (this is discussed in ‘My early years as a physicist in Poland’ reprinted in ‘War and Peace: The life and work of Sir Joseph Rotblat’ p39-55). Also in 1939 he was invited to study in Paris (through Polish connections with Marie Curie) and with James Chadwick at Liverpool University winner of the Nobel Prize for the discovery of the neutron. Chadwick was building a particle accelerator called a ‘cyclotron’ to study fundamental nuclear reactions and as he wanted to build a similar machine in Warsaw he decided to join Chadwick in Liverpool.

Liverpool University

Rotblat travelled to England alone in 1939 as he could not afford to support Tola there. At Liverpool University, Chadwick awarded him the Oliver Lodge Fellowship and now, with sufficient funds, returned home in the summer of 1939 with the intention of bringing his wife back to England. He planned to return to England in late August 1939 but Tola fell ill and he returned to Liverpool alone with the expectation that she would follow. However, war broke out as Poland was invaded by Germany on September 1 1939 and Tola was stranded. Rotblat made increasingly desperate attempts to bring her out of Poland through Belgium, Denmark or Italy but these attempts failed as borders closed across Europe. She is believed to have died in the inhumane conditions of the Warsaw Ghetto. This event affected him deeply for the rest of his life.

Towards the end of 1939 he began experiments in Liverpool that demonstrated that the nuclear bomb was feasible, but it would require a massive technological effort to produce sufficient quantities of the Uranium isotope required to manufacture a bomb.

Rotblat was wrestling with his conscience during this period and when back in England asked himself the question “What should I do? Should I begin to work or not ?” clearly meaning working on the bomb (see ‘Leaving the Bomb Project’ reprinted in Joseph Rotblat: Visionary for Peace’ p281-288). He considered himself a ‘pure scientist’ and it was not right to work on weapons of mass destruction. However, he was well aware that other scientists need not necessarily share his convictions and in particular German scientists. Put simply, if Hitler had the bomb he would win the war. When Poland was overrun he decided to work on the bomb. His belief was that we needed to work on the bomb in order that it should not be used. In other words, if Hitler can have the bomb, then the only way in which we can prevent him from using it against us would be if we also had it and threatened to retaliate. And this was the argument which he used at the time to enable him, in all conscience, to begin to work. In the beginning of 1944 Rotblat went with the Chadwick group to Los Alamos, New Mexico to work on the Manhattan Project to develop the atomic bomb. He was to return to Liverpool in late 1944 and in 1945 to become Director of Research in Nuclear Physics following a series of dramatic and life changing events.

Manhattan Project

Rotblat arrived at Los Alamos in March 1944 and soon became ambivalent about his involvement and he made no significant contribution to the development of the bomb and even complained of having nothing to do (this is discussed in the British Library recorded interviews and stated explicitly by Brian Cathcart in his obituary in ‘The Independent’ 2 January 2002). However, this time at Los Alamos was the pivotal intellectual experience of his life while the loss of Tola can be seen as the central emotional experience. He said “I was in Los Alamos for less than a year. Well, I came in the beginning of 1944, and left by the end of 1944. As soon as I came to Los Alamos, I realised that my fear about the Germans making the bomb was ungrounded, because I could see the enormous effort which was required by the American(s), with all their resources practically intact, intact by the war – everything that you wanted was put into the effort. Even so, I could see that it’s still far away, and that by that time the war in Europe was showing that Hitler is going to be defeated, and I could see that probably the bomb won’t be ready; even that Hitler wouldn’t have it in any case. Therefore I could see this from the beginning, that my being there, in the light of the reason why I came to work on it, was not really justified. But nevertheless, I could not be sure that the Germans would not find a shortcut maybe and they could still make the bomb. Therefore I kept on working together with the other people, although I was very unhappy about having to work on it. But as soon as I learned, towards the end of 1944, that the Germans have abandoned the project, in fact a long time before, I decided that my presence there was no longer justified, and I resigned and I went back to England.”(see ‘Leaving the Bomb Project’ reprinted in Joseph Rotblat: Visionary for Peace’ p281-288).

Chadwick was highly concerned that a Briton was the first to leave the Manhattan Project and the Americans regarded him as a security risk. An incompetent effort was made to ‘fit him up’ as a Russian spy, fearing that he would fly to Russia (he had learned to fly while in America) and divulge the secrets of the bomb. The Americans continued to regard him as a security risk and he was denied an entry visa for many years.

St. Bartholomew’s Hospital Medical College

Rotblat was appalled at the use of atomic bombs on Hiroshima and Nagasaki. Perhaps as a part of his reaction to the horrors of the atomic bomb he became interested in the medical uses of nuclear radiation. In 1950 he was appointed Professor of Physics to St. Bartholomew’s Hospital Medical College until retirement in1976. During this period he made significant contributions (together with Professor Patricia Lindop) to the understanding of the effects of high energy radiation on mice. He built a 15 MeV electron linear accelerator to enable the study of the biological effects of high energy gamma rays on living organisms. He made significant contributions to the understanding of the effects of radiation on living organisms, especially those of fertility and aging. He also became interested in the effects of radiation from the atmospheric testing of nuclear weapons. In particular he researched the hazards associated the bone seeking isotope Strontium 90 with a view to establishing safe levels of exposure. He researched the nature of the fallout from the American nuclear test at Bikini Atoll and made public the type of bomb used (a fission fusion fission device) and the large amounts of radiation released. Rotblat became increasingly more politicised resulting in his growing involvement in the campaign to rid the world of nuclear weapons, for which he is best known.

Pugwash and Nuclear Disarmament

In 1946, Rotblat took the lead in setting up the British Atomic Scientists Association to stimulate public debate and included many leading scientists. It adopted a non-political agenda and was wound down and ended in 1959, but Rotblat went on to be a founding member of the Campaign for Nuclear Disarmament. He collaborated with Bertrand Russell and helped launch the “Russell-Einstein Manifesto” in 1955. Russell had written to Einstein saying that “eminent men of science should draw the attention of world leaders to the impending destruction of the human race” (The Russell-Einstein Manifesto reprinted in ‘Joseph Rotblat: Visionary for Peace’ p263-266). The ‘Russell-Einstein Manifesto’ called for a conference of scientists to discuss nuclear disarmament and the abolition of war. This led to the first Pugwash conference in July 1957, funded by a Canadian railway millionaire, Cyrus Eaton, on the condition that it met at Eaton’s home in Pugwash, Nova Scotia. Twenty-one international scientists attended, together with a lawyer, from ten countries, East and West.

Conferences followed almost once a year with most participants being distinguished scientists from Great Britain, the USA and Soviet Union. The key founding principle was that participants attended as individuals and not representatives of government. Observers, however, from organisations such as the United Nations, UNESCO were welcome. Rotblat was Secretary-General of Pugwash from 1957 to 1993, Chairman of British Pugwash from 1980 to 1988 and President of Pugwash from 1988 to 1997.

Pugwash has never cultivated extensive publicity but has been highly influential and, for example, was instrumental in achieving agreement on the 1963 Partial Test Ban Treaty. Also, Pugwash can be credited with helping to establish links between the US and Vietnam in the late 1960s, the negotiation of the 1972 Biological Weapons Convention and the 1972 Anti-Ballistic Missile Treaty. Rotblat can claim credit for these landmark achievements.


Joseph Rotblat made massively important contributions to science, to combating the proliferation of nuclear weapons and the promotion of peace. Bertrand Russell, in his

autobiography, summed up his work with these words: “He can have few rivals in the courage and integrity and complete self-abnegation with which he has given up his own career (in which, however, he still remains eminent) to devote himself to combating the nuclear peril as well as other, allied devils”. His achievements were recognised with the award in 1992, with Hans Bethe, of the Einstein Peace Prize. In 1995 he was elected to The Royal Society and was awarded the Nobel Peace Prize in the same year shared with the Pugwash Conferences. He was appointed KCMG in 1998. However, he could well have been most proud of Mikhail Gorbachev’s statement that Pugwash conferences and papers helped guide foreign policy resulting in the reduction in temperature of the Cold War.

Joseph Rotblat at 89 said, “We scientists have to realise that what we are doing has an impact not only on the life of every individual, but also on the whole destiny of humankind…all of us who want to preserve the human race owe an allegiance to humanity; and it’s particularly the job of scientists, because most of the dangers to the world result from the work of scientists.” From his Nobel Lecture in Oslo, “the quest for a war free world has a basic purpose, survival. But if in the process, we learn to achieve it by love rather than by fear, by kindness rather than by compulsion, if in the process, we learn to combine the essential with the enjoyable, the expedient with the benevolent, the practical with the beautiful, this will be an excellent incentive to embark on this great task. But above all, remember your humanity (J. Rotblat ‘Remember Your Humanity’ reprinted in ‘Joseph Rotblat: Visionsry for Peace’ p315-322). Joseph Rotblat was a truly great man and the conscience of the Nuclear Age.

References and sources

Joseph Rotblat’s papers (some 4 tonnes in weight !) are currently being processed by the University of Bath and the archives will reside in Churchill College, Cambridge. I am told that this process will take about 2 more years to complete.

I have used 2 sound archive resources:

British Library Sound Archive (call number F7208). This is an exhaustive, some 20 hours, series of interviews given to Katherine Thompson in his own home between May 1999 and 2002. An invaluable source although full transcripts, to my knowledge, are not available.

National Security Archive-Cold War Interviews (November 15,1998, Episode 8, SPUTNIK). This is a non-governmental, non-profit organisation of scientists and journalists providing a ‘home’ for former secret U.S. Government information obtained under The Freedom of Information Act. Full transcripts are available on the internet.

‘War and Peace: The Life and Work of Sir Joseph Rotblat’ edited by Peter Rowlands and Vincent Attwood. Liverpool University Press 2006.

‘Joseph Rotblat: Visionary for Peace’ edited by R. Braun, R. Hinde, D. Krieger, H. Kroto, and S. Milne. Wiley-Vich 2007.

‘Joseph Rotblat: Influences, Scientific Achievements and Legacy’, Physics Education, 40, October 2008, in press.

Dr. Martin Underwood is a member of Pugwash UK and was a colleague and friend of Joseph Rotblat.