The concept of the United Nations as an international organisation to replace the ineffective League of Nations was formulated and negotiated among the delegations from the U.S. , the U.K. , the Soviet Union and China at the Dumbarton Oaks Conference in 1944 . Winston Churchill urged Roosevelt to restore France to its status of a major Power after the liberation of Paris in August 1944 . After months of planning , the UN Conference on International Organization opened in San Francisco in April 1945 attended by 50 governments and a number of non-governmental organisations involved in drafting the United Nations Charter . The heads of the delegations of the sponsoring countries took turns as chairman of the plenary meetings beginning with Anthony Eden of Britain . The UN officially came into existence on 24 October 1945 upon ratification of the Charter by the five permanent members of the Security Council — the U.S. , the U.K. , France , the Soviet Union and the Republic of China — and by a majority of the other 46 signatories
UN Conference on International Organization
United Nations Conference on International Organization
United Kingdom and the United Nations