To what extent was colonial expansion the main factor in the decline of the East African slave trade?

The question requires that candidates consider the merits or otherwise of the suggestion that colonial expansion was the main factor in the decline of the East African slave trade. Candidates may refer to the British decision to outlaw the slave trade in 1807, and slavery itself in 1834. Abolition of the trade was one of the factors that motivated explorers such as David Livingstone, who viewed formal colonization as key to realizing this goal. As Britain extended its influence, its consul in Zanzibar, John Kirk, pressured the Sultan to end the trade. His decision to close the market in 1873 was a crucial moment in its demise. Candidates may argue that the presence of the Royal Navy in the Indian Ocean was another crucial factor in the suppression of the trade. They may also note that Ethiopia was not colonized and that slavery persisted in that country, or that the Germans formally abolished slavery in their territories, but did little to enforce this. Candidates’ opinions or conclusions will be presented clearly and supported by appropriate evidence.