Why did Britain attack Lagos in 1851?

In 1851, Britain attacked Lagos primarily to suppress the slave trade and protect the Egba people. By shelling the city, the British forces expelled the reigning oba, Kosoko, and restored his uncle, Akitoye, to power.1

Akitoye was viewed by the British as a leader more willing to cooperate in their campaign to abolish the slave trade in the region. This military intervention was part of a broader British effort to shift local economic activity away from the trade in enslaved people and toward the trade in palm oil, which they believed would serve as a more legitimate commercial alternative.1