Who were the UK's enemies in World War 2?
The following countries were enemies to the United Kingdom during World War 2, Germany, Italy, Austria, Hungary, Romania, Yugoslavia, Japan, Mexico, Argentina, Bolivia,and Uraguay.
During world war 2 Japan had the biggest army in the east but in world war 2 this was not what matters it was the numbers or aircraft carriers you had. Japan had 9 and U.S.A had 11. One of the largest in the world next to the United States, Russia, Germany and UKs. Note that Japan had in fact taken over almost all of Asia.