After World War I Britain was overwhelmed and desired to avoid any other was, the country played a leading role in the League of Nations. At interwar disarmament conferences like the ones in Washington (1921-1922) and London (1930) that limited naval size. At the 1919 peace conference Germany could have been treated unfairly, the British government followed appeasement, a policy dealing with Adolf Hitler’s Germany after 1933. Then Prime Minister Neville Chamberlain gave all efforts to keep the peace at all costs, also consented without protest to the Nunich Part of 1938, which gave Germany the Sudetenland portion of Czechoslovakia. Only after the German added in on Praque (March 1939) did Britain make pledges to Poland and Romania.

Then Hitler invaded Poland in September 1939, Britain and France declared war. They entered the war on September 3, 1939. "The Phony War" followed in the spring of 1940 by the German invasion of Denmark, Norway, Holland, Belgium and France. Then Winston Churchill, who has joined the cabinet in 1939, replaced Chamberlain