<P> In mid-1944, the delegations from the Allied "Big Four", the Soviet Union, the UK, the US and China, met for the Dumbarton Oaks Conference in Washington, D.C. to negotiate the UN's structure, and the composition of the UN Security Council quickly became the dominant issue . France, the Republic of China, the Soviet Union, the UK, and US were selected as permanent members of the Security Council; the US attempted to add Brazil as a sixth member, but was opposed by the heads of the Soviet and British delegations . The most contentious issue at Dumbarton and in successive talks proved to be the veto rights of permanent members . The Soviet delegation argued that each nation should have an absolute veto that could block matters from even being discussed, while the British argued that nations should not be able to veto resolutions on disputes to which they were a party . At the Yalta Conference of February 1945, the American, British, and Russian delegations agreed that each of the "Big Five" could veto any action by the council, but not procedural resolutions, meaning that the permanent members could not prevent debate on a resolution . </P> <P> On 25 April 1945, the UN Conference on International Organization began in San Francisco, attended by 50 governments and a number of non-governmental organizations involved in drafting the United Nations Charter . At the conference, H.V. Evatt of the Australian delegation pushed to further restrict the veto power of Security Council permanent members . Due to the fear that rejecting the strong veto would cause the conference's failure, his proposal was defeated twenty votes to ten . </P> <P> The UN officially came into existence on 24 October 1945 upon ratification of the Charter by the five then - permanent members of the Security Council and by a majority of the other 46 signatories . On 17 January 1946, the Security Council met for the first time at Church House, Westminster, in London, United Kingdom . </P> <P> The Security Council was largely paralysed in its early decades by the Cold War between the US and USSR and their allies, and the Council generally was only able to intervene in unrelated conflicts . (A notable exception was the 1950 Security Council resolution authorizing a US - led coalition to repel the North Korean invasion of South Korea, passed in the absence of the USSR .) In 1956, the first UN peacekeeping force was established to end the Suez Crisis; however, the UN was unable to intervene against the USSR's simultaneous invasion of Hungary following that country's revolution . Cold War divisions also paralysed the Security Council's Military Staff Committee, which had been formed by Articles 45--47 of the UN Charter to oversee UN forces and create UN military bases . The committee continued to exist on paper but largely abandoned its work in the mid-1950s . </P>

Where was the first un security council meeting held