 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.The first meetings of the United Nations General Assembly and the Security Council took place in London beginning on 6 January 1946.