Winston Churchill considered Patrick Blackett, the Nobel-winning physicist and future President of the Royal Society, to be a security risk. New evidence for this suspicion can be found in files recently released at the National Archives, having been closed to public eyes for 63 years.

Patrick Blackett was one of the stars of the Cavendish, the physics laboratory of the University of Cambridge where so many significant discoveries in sub-atomic physics were made under Ernest Rutherford’s leadership before the Second World War. Blackett’s area of research was cosmic rays, and it was for techniques he developed in the early 1930s to record automatically the passage of these particles that he was awarded the Nobel Prize for Physics in 1948. Before Cambridge, Blackett had served in the Navy, a fighting forces experience that would later prove significant.

Blackett was a socialist as well as one of the most accomplished experimental physicists working in mid-twentieth century Britain. His political convictions were not unusual. Indeed the late 1930s saw a considerable movement of scientists who wanted to ally science for social responsibility, left-wing politics and planning. There was, however, an equally articulate opposition, who argued that science must be autonomous, free to plan its own scientific agendas, if it was to flourish. This division was deep, and deeply important for framing debates about science and government.

Blackett’s expertise gave him a place on two crucial committees that shaped military technology, one on radar and the other on the military applications of nuclear fission. The second of these, known as the MAUD Committee, examined the consequences of the calculations of Frisch and Peierls that a relatively small quantity of uranium could be used to make a bomb of enormous destructive power. When the MAUD Committee reported positively in 1941, Blackett was the only member who dissented from the view that a British atomic bomb could be made in wartime Britain (Nye 2004, p. 74). Indeed the bomb project subsequently moved to the Manhattan Project in the United States, again against Blackett’s advice.

In 1948, Blackett made public his views about the subject in a dense but corruscating book, The Military and Political Consequences of Atomic Energy. As historian Graham Farmelo (2013) has argued, public attention to Blackett’s arguments was amplified by the fact that, quite contingently, he had been awarded the Nobel Prize that year. Its publication prompted George Orwell to include Blackett’s name in a list of 38 ‘pro-Communist writers and intellectuals’ he submitted to the Foreign Office’s Information Research Department (Farmelo 2013, Nye 2004 p. 92) in 1949.

By then Blackett had already been investigated by the Security Service because of his association with Communists. Four fat files released in 2010 (National Archives KV 2/3217-3220) contain the paper trail from the 1930s until the early 1950s. In 1941, at the time of the MAUD Committee, Winston Churchill had asked MI5 to “‘see if they had anything against’ him, but had been told that he was ‘entirely harmless'”; Churchill, unassuaged, had lobbied to keep Blackett away from Britain’s atomic bomb project, codenamed “Tube Alloys” (Farmelo 2013).

The new evidence is in keeping with this pattern of suspicion. The file released in January 2016 come from Winston Churchill’s peacetime administration. In June 1952, Peter Thorneycroft, President of the Board of Trade, had written to Churchill reporting on ‘two cases where individuals known to have close associations with Communists hold apppointments on statutory bodies’ for which Thorneycroft was responsible (National Archives PREM 11/263). One was the economist Joan Robinson, a member of the Monopolies Commission. The other was Blackett, as a member of the National Research Development Corporation, a public patent-holding body. Robinson was less of a concern – she was about to retire. Blackett’s case was therefore different. Nevertheless, Thorneycroft was satisfied that Blackett was not ‘dealing with work involving information of security value’, and possessed the confidence of his colleagues, and therefore there was no justification in taking action to remove Professor Blackett from the Corporation’s Board.

Churchill, however, again was not satisfied. ‘I should like to have the Home Sec’s opinion’, he scribbled on Thorneycroft’s note. Sir David Maxwell Fyfe, the Home Secretary, quickly responded. He discussed the matter with the Director General of MI5 and advised Churchill that Robinson should be allowed quietly to retire, but that

I think Professor Blackett must be regarded as a security risk: he seems ingenuous and has active Communists about him. But for the reasons given by the President I agree that he should remain a member of the Board of the National Research Development Corporation.

Churchill then wrote back to Thorneycroft saying:

I sent your minute of June 17 about two people known to have close associations with Communists to the Home Secretary and he and I agree with your conclusions.

The conclusions being, presumably, that Blackett was both a security risk but also someone who could be tolerated, just about, to work for the non-sensitive Corporation.

Blackett continued to have an influential career, building up physics departments at Manchester University and Imperial College, where he oversaw the beginnings of Jodrell Bank and contributed geomagnetic evidence that would be crucial to establishing the later theory of plate tectonics, respectively. He was an active supporter of science in newly independent India. And he served as President of the Royal Society from 1965 to 1970.

Blackett’s treatment during the years of anti-Communism, during which physicists such as Klaus Fuchs were revealed as atomic spies, can be compared to the fate of his American contemporary J. Robert Oppenheimer. The charismatic Oppenheimer had been the civilian scientist leader at Los Alamos during the Manhattan Project. But during the late 1940s and 1950s he too had been dogged by suspicions of Communist sympathy. These corrosive doubts culminated, in 1954, in the ‘Oppenheimer Trial’, in which the physicist was also declared a security risk while also being “loyal”. Oppenheimer’s judgement was made in public – indeed it was front-page news in the New York Times – while Blackett’s was kept secret.

(Incidentally, there is one other, extraordinary, point of connection between Oppenheimer and Blackett. The younger American had visited the Cavendish in 1925 and Blackett had been one of his tutors. But this period of European travel was also one of intense personal, psychological trouble for the highly-strung Oppenheimer. He felt so “miserable in Cambridge, so unhappy, that he used sometimes to get down on the floor, groaning and rolling from side to side”. At the peak of this crisis, Oppenheimer, consumed ‘by feelings of inadequacy and intense jealousy, … “poisoned” an apple with chemicals from the laboratory and left it on Blackett’s desk’ (Bird and Sherwin 2005 p. 43, p. 46))

Sources

National Archives KV 2/3217-3220. Patrick Maynard Stuart BLACKETT

National Archives PREM 11/263 Request from Prime Minister for advice on Dr Joan Robinson and Professor Blackett

Kai Bird and Martin J. Sherwin, American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer, New York: Alfred A. Knopf, 2005

Graham Farmelo, Churchill’s Bomb: A Hidden History of Science, War and Politics, London: Faber & Faber, 2013

Mary Jo Nye, Blackett: Physics, War and Politics in the Twentieth Century, Cambridge, MA: Harvard University Press, 2004