Answer:
Czechoslovakia in March 1939
Explanation:
Britain saw that Hitler was lying in Munich Agreement when he agreed to not capture the remainder of Czechoslovakia.
Germany has violated the Treaty of Versailles by invading Rhineland (France) in 1936. With the annexation of Austria and the capture of the Sudetenland in 1938, to the control of Czechoslovakia in March 1939 and with the annexation of Poland on September 1939, Britain declared the war against Germany after two days.
