I didn't know there were chattel manning the factories in Merry Old England.
No but historians like Kenneth Pomeranz argue the massive amounts of liquid capital, coupled with all the specie and bullion looted by Spain and Portugal, that created the liquid wealth necessary for those investments in the first place. Easily the most profitable aspect of the British economy in the 18th century was the sugar plantations of the Caribbean. That's before one talks about the direct link between Southern cotton, Northern industry, and US capital accumulation in the Antebellum period.
The thing that's worth pointing out is there was an intensive, cash-crop plantation system at work in the Americas and the Caribbean that had no parallel in the Roman Empire. Slaves in Rome were not as thoroughly dehumanized as was the case in chattel slave situations and enjoyed greater legal (and real) protections. It was possible, though not easy or likely, for a slave to become a free citizen. Voluntary manumission happened in the antebellum US but slaves working their way out was almost unheard of and the degree of coercion was far greater.