The Lyttleton Constitution of 1954 — named for the Colonial Secretary Oliver Lyttleton — converted Nigeria from a unitary state with regional governments to a true federation. Each Region (Northern, Western and Eastern; Southern Cameroons joined as a quasi-Region) had a Premier and a House of Assembly; the centre had a Federal Prime Minister.
Lagos became a Federal Territory separate from the Western Region — over Awolowo's protest. The Constitution was the immediate ancestor of the Independence Constitution of 1960 and bequeathed to independent Nigeria its three-region structure, regional revenue allocation, and the centre-regions tension that would explode in 1966.