The famous 20th-century British Prime Minister known for his leadership during World War II is Winston Churchill. He served as Prime Minister from 1940 to 1945, navigating the United Kingdom through some of its darkest days during the war. Churchill was renowned for his stirring speeches that rallied the nation and instilled hope. His firm stance against Nazi Germany and efforts in forging alliances, particularly with the United States, played a crucial role in the Allied victory. After the war, Churchill lost the election in 1945 but continued to be a significant political figure and commentator on global affairs.