Sir Winston Leonard Spencer-Churchill (30 November 1874 – 24 January 1965) was a British politician who was the Prime Minister of the United Kingdom from 1940 to 1945 and again from 1951 to 1955. Widely regarded as one of the greatest wartime leaders of the 20th century, Churchill was also an officer in the British Army, a historian, a writer (as Winston S. Churchill), and an artist. Churchill is the only British Prime Minister to have won the Nobel Prize in Literature since its inception in 1901, and was the first person to be made an honorary citizen of the United States.

Churchill was born into the aristocratic family of the Dukes of Marlborough, a branch of the Spencer family. His father, Lord Randolph Churchill, was a charismatic politician who served as Chancellor of the Exchequer; his mother, Jennie Jerome, was an American socialite. As a young army officer, he saw action in British India, the Sudan, and the Second Boer War. He gained fame as a war correspondent and wrote books about his campaigns.

At the forefront of politics for fifty years, he held many political and cabinet positions. Before the First World War, he served as President of the Board of Trade, Home Secretary, and First Lord of the Admiralty as part of Asquith’s Liberal government. During the war, he continued as First Lord of the Admiralty until the disastrous Gallipoli Campaign caused his departure from government. He then briefly resumed active army service on the Western Front as commander of the 6th Battalion of the Royal Scots Fusiliers. He returned to government as Minister of Munitions, Secretary of State for War, and Secretary of State for Air. In 1921–1922 Churchill served as Secretary of State for the Colonies, then Chancellor of the Exchequer in Baldwin’s Conservative government of 1924–1929, controversially returning the pound sterling in 1925 to the gold standard at its pre-war parity, a move widely seen as creating deflationary pressure on the UK economy. Also controversial were his opposition to increased home rule for India and his resistance to the 1936 abdication of Edward VIII.

Out of office and politically “in the wilderness” during the 1930s, Churchill took the lead in warning about Nazi Germany and in campaigning for rearmament. At the outbreak of the Second World War, he was again appointed First Lord of the Admiralty. Following the resignation of Neville Chamberlain on 10 May 1940, Churchill became Prime Minister. His steadfast refusal to consider defeat, surrender, or a compromise peace helped inspire British resistance, especially during the difficult early days of the war when the British Commonwealth and Empire stood alone in its active opposition to Adolf Hitler. Churchill was particularly noted for his speeches and radio broadcasts, which helped inspire the British people. He led Britain as Prime Minister until victory over Nazi Germany had been secured.

After the Conservative Party lost the 1945 election, he became Leader of the Opposition to the Labour Government. After winning the 1951 election, he again became Prime Minister, before retiring in 1955. Upon his death, Elizabeth II granted him the honour of a state funeral, which saw one of the largest assemblies of world statesmen in history. Named the Greatest Briton of all time in a 2002 poll, Churchill is widely regarded as being among the most influential people in British history, consistently ranking well in opinion polls of Prime Ministers of the United Kingdom.