Another argument used by the pro-slavery lobby was that economically Britain was dependent on slavery to create wealth and many have invested large amounts of capital in the trade. This clip needs using with CAUTION as it reflects the language of the time, which is unacceptable for use today:
That the Value of the Lands depends on the Cultivation of them by Means of Negro Labourers...; and that it continues to be the Practice of all the Nations of Europe in the West Indies, to employ Negroes only... founded on the Experience that Europeans must soon sink under the inclemency of the Climate...
Under a Faith that [Britain] would never impede them in their Cultivation by prohibiting the Importation of Negroes, they have erected very extensive Works, and invested a great Capital in the Purchase of Negroes for carrying on the Manufacture of Sugar and Rum, so that the said island... is now become a valuable Sugar Colony.
Recorded in the 'Journal of the House of Commons' (20 May 1789)