Department of State Atomic Energy Files

Memorandum of Conversation, by Mr. Edmund A. Gullion, Special Assistant to the Under Secretary of State (Lovett)

top secret

Mr. Maclean called to see me and stated that he had a communication to make which would probably have been delivered by the Ambassador to the Secretary or Mr. Lovett had either been in town.

He stated that he was directed to inform the Department that since the beginning of last year United Kingdom had been engaged on research and development work in atomic weapons. This work was carried on, not by the usual organizations charged with scientific development or experiments in weapons, but by a special section of the Ministry of Supply under Lord Portal.1 The time had now come when the U.K. planned to let it be known publicly that such activity was going forward. The British believed that was necessary and desirable because:

The work had now reached the stage where security might be endangered by uncontrolled speculation as to what was being done.
It was becoming increasingly difficult to keep completely secret.
The present complete secrecy was handicapping prosecution of the work.

Consequently the British planned to announce casually, possibly in response to a planned press question, that the U.K. was developing modern post-war weapons including atomic weapons.2 This statement would only be made following a consultation between the authorities responsible for atomic weapons with a special press committee. The British believe that this consultation would insure against further embarrassing questions from the press and would restrict speculation to a minimum. In the unlikely event that this result did not appear obtainable, the British might defer making the projected indirect disclosure.

The Canadians as well as ourselves are being informed. The British did not appear to expect comments from us, but merely wanted to put us on notice.

  1. Lord Portal of Hungerford, British Chief of Air Staff, 1940–1945.
  2. Secretary of Defense Forrestal received similar notification from Admiral Sir Henry Moore on March 31 (Walter Millis (ed.), The Forrestal Diaries (New York: Viking Press, 1951), pp. 406–407.) The contemplated announcement was made on May 12 by A. V. Alexander, Minister of Defence, in answer to a question in the House of Commons (Parliamentary Debates; House of Commons, May 12, 1948, vol. 450, cols. 2128–2129.)