The abolition of the slave trade by Britain in 1807 presented the slave traders of Guinea with a virtual monopoly of the West Africa slave trade with Brazil. Despite the Brazilian and Portuguese governments agreeing to stop this traffic in the 1830s, it probably continued at 18th-century levels, and only declined significantly after 1850, when the British government put pressure on Brazil to enforce its existing ban on the import of slaves. The last significant consignment of West African slaves reached Brazil in 1852.