Free trade combined with emancipation to severely damage sugar production in the British Caribbean. The imperative to shore up the plantation economy led Whig-Liberal proponents of free-trade anti-slavery to commit the imperial government to the sponsorship of assisted immigration as a chief solution to high labour costs in the West Indies. The Caribbean migrant labour traffic subordinated humanitarianism to the imperative to preserve the sugar monoculture in the British West Indies, replacing enslaved labourers with imported Black and Brown workers who remained far more constrained than the free white immigrants who gradually supplanted convicts as a labour source in Australia. In its haste to keep the British Caribbean safe for sugar, the imperial state risked the lives of thousands Africans ‘liberated’ by the Royal Navy from the bellies of slave ships, prematurely entangling them in hazardous Caribbean sugar work.