British Prime Minister Sir Anthony Eden resigns from office following his failure to retake the Suez Canal from Egyptian sovereignty.

The prime minister of the United Kingdom is the head of government of the United Kingdom. The prime minister advises the sovereign on the exercise of much of the royal prerogative, chairs the Cabinet, and selects its ministers. Modern prime ministers hold office by virtue of their ability to command the confidence of the House of Commons, so they are invariably members of Parliament.

Robert Anthony Eden, 1st Earl of Avon, was a British politician who served as Prime Minister of the United Kingdom and Leader of the Conservative Party from 1955 until his resignation in 1957.

The Suez Crisis, also known as the second Arab–Israeli war, the Tripartite Aggression in the Arab world and the Sinai War in Israel, was a British–French–Israeli invasion of Egypt in 1956. Israel invaded on 29 October, having done so with the primary objective of re-opening the Straits of Tiran and the Gulf of Aqaba as the recent tightening of the eight-year-long Egyptian blockade further prevented Israeli passage. After issuing a joint ultimatum for a ceasefire, the United Kingdom and France joined the Israelis on 5 November, seeking to depose Egyptian president Gamal Abdel Nasser and regain control of the Suez Canal, which Nasser had earlier nationalised by transferring administrative control from the foreign-owned Suez Canal Company to Egypt's new government-owned Suez Canal Authority. Shortly after the invasion began, the three countries came under heavy political pressure from both the United States and the Soviet Union, as well as from the United Nations, eventually prompting their withdrawal from Egypt. The Crisis demonstrated that the United Kingdom and France could no longer pursue their independent foreign policy without consent from the United States. Israel's four-month-long occupation of the Egyptian-occupied Gaza Strip and Egypt's Sinai Peninsula enabled it to attain freedom of navigation through the Straits of Tiran, but the Suez Canal was closed from October 1956 to March 1957.