from Wikipedia:
Slavery in Great Britain existed and was recognized from before the Roman occupation until the 12th century, when chattel slavery disappeared after the Norman Conquest. Former slaves merged into the larger body of serfs in Britain and no longer were recognized separately in law or custom.[1][2]
Footnotes:
Maitland, Frederic; Pollock, Frederick (1895), The History of the Laws of England Before the Time of Edward I, Cambridge: Cambridge University Press, p. 34.
David A. E. Pelteret, Slavery in Early Mediaeval England: From the Reign of Alfred until the Twelfth Century (1995)
"Chattel slavery" means ownership of one person by another. This differs from serfdom, which means the right to buy a person's labour without the consent of that person. As I noted above, the last vestiges of this in Britain ended in the early eighteenth century.
Please stop the offensive comparisons with the transatlantic slave trade, which only ended in the nineteenth century, and with the slave trade in both men and women that still exists today.