What caused the British Empire to take military action in the Suez Crisis?

The primary cause of the British Empire's military action during the Suez Crisis was the nationalization of the Suez Canal by Egyptian President Gamal Abdel Nasser in 1956. The Suez Canal was crucial for international trade and a vital route for oil transport, particularly for British and French interests. By nationalizing the canal, Nasser aimed to assert Egypt's sovereignty and to use the canal's revenues for national development projects. This move directly threatened British and French economic interests and their strategic control over this vital passageway, prompting them to take military action in collaboration with Israel in an effort to regain control over the canal and counteract what they saw as rising Arab nationalism.

While oil control and relations with the USSR were factors in the broader context of the Cold War, the immediate impetus for the military intervention was the nationalization decision itself. Therefore, the focus on the Suez Canal's nationalization clearly delineates the motivations behind Britain's involvement in the crisis.