"Suez Crisis"

Suez Canal
GNU Free Documentation LicenseSuez Canal - Credit: Clipper, Wikimedia
In 1956, Egypt nationalised the Suez Canal, formally a neutral zone under British protection (and control).  Because of the vital importance of the canal to Britain and France in maintaining their eastern influence and power, the two European nations together with Israel launched an attack on Egypt.

The military operation to re-take the Canal zone was successful, but it led to widespread international condemnation, most importantly from the USA, forcing France and Britain to withdraw.

The loss of Suez, for many people, marked the de facto end of the British Empire.