Britain's War Against the Slave Trade: The Operations of the Royal Navy’s West Africa Squadron, 1807–1867

Not sure it’s a war and more a police action, although Britain spent significant capital and lives to the effort. The Royal Navy's West Africa Squadron (1808–1860s): Britain waged a decades-long moral, diplomatic, and military campaign to abolish slavery, beginning with the Slave Trade Act of 1807, which banned the trade within the British Empire. To enforce an 1807 ban, Britain deployed a naval fleet. At its peak in the mid-19th century, this squadron tied up over 14% of the entire Royal Navy's fleet and personnel to intercept slave ships. They liberated tens of thousands of enslaved people and settled many in the freed-slave colony of Freetown, Sierra Leone. [1, 2, 3, 4, 5]