The final suppression of the Brazilian slave trade during the years 1850–1—twenty years after it had been declared illegal by treaty with Britain and more than forty years after Britain had abolished her own share of the transatlantic trade and made her first official abolitionist overtures in Lisbon and Rio de Janeiro—did not immediately remove the slave trade question from Anglo-Brazilian relations. On the contrary, both the memory and the legacy of a conflict so protracted and at times so bitter poisoned relations between the two countries for many years to come. And serving most effectively to keep the slave trade controversy alive was the continued existence of the Aberdeen Act long after the trade had been abolished.

At the time of its passage in 1845, Lord Aberdeen had looked upon his Act, like the Palmerston Act before it, as an exceptional, temporary measure; it would be repealed, he had indicated, either when Brazil signed an effective anti-slave treaty with Britain—as Portugal had done in 1842—or when Brazil co-operated with Britain and herself abolished the trade. Towards the end of 1851, believing that by their actions they had now clearly demonstrated their desire and their ability to put down the slave trade and to prevent its revival, the Brazilian government made a second attempt—the first had been made, prematurely, in October–November 1850—to persuade Britain to repeal the Act which had always been deeply resented in Brazil or, at the very least, not to enforce it in Brazilian inland and territorial waters.