Letter from Clement Attlee, Prime Minister (10, Downing Street) to WSC marked "top secret" enclosing a note about the circumstances in which the clause in the Quebec Agreement was allowed to lapse which provided that neither the United States nor the United Kingdom would use the [atomic] bomb against third parties without the consent of the other. He explains: that the Americans were keen to get rid of the clause because Congress had not been informed about it and it went beyond the terms which the President has the power to agree; that the technical provisons about the exchange of information and raw materials remain in place; that the United Kingdom wished to be free of restrictions on the use of atomic energy for industrial purposes; the need for greater co-operation with the United States since the MacMahon [sic] Act; and that it was recognised that friendship and co-operation would be more significant than written agreements. He ends by paying tribute to WSC's efforts in securing the Quebec Agreement. Includes enclosure entitled "Top Secret: Atomic Energy: The Quebec Agreement of 1943" on the end of co-operation between the United States and the United Kingdom and Canada as a result of the McMahon Act; the "modus vivendi" and renewal of limited co-operation; the omission from the "modus vivendi" of clauses dealing with mutual consent for use of the bomb and industrial and commercial aspects; and limited exchange of technical information. Signed typescript.