Why did the Northern region receive internal self-government later than the Western and Eastern regions?

The Northern region of Nigeria received internal self-government in 1959, two years after the Western and Eastern regions, at its own request.12

This delay was driven by the concerns of Northern leaders, who feared that their region would be disadvantaged in the operation and opportunities of the federal government if it transitioned to self-government too quickly. Specifically, Northern leaders sought additional time to "catch up" with the educationally advanced Southern regions, ensuring that the North could maintain an equal share of influence and participation within the federal structure. This disparity in development was largely a result of the colonial era, during which Western education and Christianity spread rapidly in the South while being strongly resisted by Muslim leaders in the North.12