At that time, the United States, the Soviet Union, Japan, Germany and Britain were all industrial powers. However, at the end of 1943, World War II entered the final stage, and the defeat of Germany, Italy and Japan fascists was decided. With the development of the military actions of the anti-fascist allies, a series of political problems arising from ending the war and arranging the post-war world need to be solved quickly, especially the coordinated military action plan of the allies in the final stage of the anti-Hitler German war. The basic principles of dealing with the defeated German "Empire", fighting against Japan and realizing international security in the post-war world objectively require the three major allies to hold a new summit.

However, at this time, although Britain's national strength is still in the forefront, it is still not enough to compare with the vast United States and the Soviet Union, and it can only be left to them to divide up the "cake" after the war.

Britain's weak national strength should start with the Boer War. Before the Boer War, Britain, an eternal empire, was fully formed. Britain follows the principle of glorious isolation and does not engage in alliances. It is the only superpower in the world. After the Boer War, Britain's national strength was greatly damaged, and Russia and other countries saw Britain's weakness-the front line was too long, trying to challenge Britain's hegemony. It can be said that from this time on, Britain began to decline. After World War II, with the help of the Bretton Woods system, the dollar's status as the world currency was established. At the same time, with the help of the Marshall Plan, the United States occupied the dominant position in the world industry and eliminated its competitors, so Britain had to retreat to the second place.

Moreover, because of the tradition of "Labour Party's mistake for the country", it once abandoned the national defense industry, which made Britain's national defense and heavy industry worse.