Hopkins Papers: Telegram

Prime Minister Churchill to the President’s Special Assistant (Hopkins)1


Prime Minister to Mr. Harry Hopkins. Personal immediate and most secret. My immediately preceding telegram.

Following is memorandum summarizing history of US–UK relations on project known as S–1 or Tube Alloys .2 (Memorandum begins.)

After the discovery in Germany in December 1938 of the fission of U 235, research proceeded in France, USA and Britain on the possibility of using this as a source of energy both for power generation and as a military explosive.

From the middle of 1940 the work in USA was organized under the S–1 Committee of NDRC and in UK under the Maud Committee of MAP and information was freely exchanged both in written documents and verbally.

Bainbridge and Lauritsen of NDRC attended Maud Committee meetings in April and July 1941 at which complete reviews of the British work were given.

In a letter dated October 11, 1941 President Roosevelt suggested to Prime Minister that they should soon correspond or converse “In order that any extended efforts may be coordinated or even jointly conducted.”3

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In December 1941 the Prime Minister replied “I need not assure you of our readiness to collaborate with the US administration in this matter”.

Meanwhile British work had been reorganized and greatly expanded under a “Director of Tube Alloys ” directly responsible to the Lord President.4 Similar reorganization took place in USA.

Professors Pegram and Urey visited Britain in November 1941. They were allowed free access to all our laboratories, so that they could study our work and new organization in detail.

Full information was also exchanged in writing (letters from Dr. Bush to Sir J. Anderson of December 23, from Mr. Brook to Mr. Hovde of January 20, from Sir J. Anderson to Dr. Bush of March 23 and from Dr. Bush to Sir J. Anderson of April 20.)

All these communications assumed on both sides complete collaboration at all stages of the project.

This policy was fully confirmed when Mr. Akers, British Director of Tube Alloys , accompanied by Professors Simon, Halban and Peierls, visited America between February and June 1942. They gave full and detailed information about all our progress and plans and were able to discuss all aspects of the project with US scientists with complete frankness on both sides.

The President and the Prime Minister discussed the question generally at Hyde Park in June 1942, and it is the Prime Minister’s clear recollection that the whole basis of the conversation was that there was to be complete cooperation and sharing of results.5

Between June and October 1942 correspondence took place between Dr. Bush and the Lord President with the object of finding the most efficient way of using the combined industrial and scientific resources of the two countries to realize the Tube Alloy project in the best interests of the United Nations.

The Lord President suggested that this would best be achieved by arranging for the joint effort to be used in building a plant in North America.

The proposal to build a plant in North America rather than in Britain was not due to any technical inability on the part of the British but to the conviction that this was best on strategic grounds and would involve the minimum interference with the joint war effort.

Throughout this correspondence there is no hint that Dr. Bush contemplated any restriction in interchange of technical information. Wording shows that object of both parties at that time was still to find best means of forwarding a joint cooperative effort.

Contemporaneously with this correspondence there was also an exchange of letters between the Lord President and Dr. Bush in which the former emphasized his conviction that the closest cooperation and exchange of technical information was essential and should be safeguarded by an agreement between the two governments for joint execution of the project and joint wartime and post-war control.

At Dr. Bush’s invitation Mr. Akers visited USA from November 1942 to end of January 1943 to inform him of our latest results and to discuss the interlocking of the programmes of the two countries.

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After being informed that the US Army was now responsible for all work beyond laboratory research and that it was proposed to tighten up exchange of information solely in the interests of secrecy, Mr. Akers was eventually, on January 7, 1943, given by Dr. Conant a memorandum on the interchange with the British and Canadians on S–1.

This memorandum is stated to derive from the basic principle “That interchange on design and construction of new weapons and equipment is to be carried out only to the extent that the recipient of the information is in a position to take advantage of this information in this war.”

The memorandum sets out the logical result of applying this principle to all phases of the S–1 project, in the light of the respective American and British programmes then envisaged. It limits drastically interchange of technical information and entirely destroys the original conception of “A coordinated or even jointly conducted effort between the two countries.”

  1. Transmitted via military channels.
  2. For the authoritative American history of the collaboration between the United States and the United Kingdom in the interchange of scientific information of military application, particularly atomic energy, from 1940 to January 1943, see Hewlett and Anderson, pp. 256–270.
  3. Roosevelt’s letter read as follows:

    “It appears desirable that we should soon correspond or converse concerning the subject which is under study by your Maud committee, and by Dr. Bush’s organization in this country, in order that any extended efforts may be coordinated or even jointly conducted. I suggest, for identification, that we refer to this subject as Mayson .

    “I send this message by Mr. Hovde, head of the London office of our scientific organization, as he can, if necessary, identify the subject more explicitly, or answer your questions concerning the form of organization by which it is now being handled in this country.” (Roosevelt Papers)

  4. Sir John Anderson.
  5. Regarding the Roosevelt–Churchill discussions of the atomic bomb project during their meetings at Hyde Park in June 1942, see Foreign Relations, The Conferences at Washington, 1941–1942, and Casablanca, 1943, p. 432.