Somerset v Stewart (1772) 98 ER 499](aka Somersett's case, or in State Trials v.XX Sommersett v Steuart) is a famous judgment of the English Court of King's Bench in 1772, which held that chattel   slavery was unsupported by the common law in England and Wales, although the position elsewhere in the British Empire was left ambiguous. Lord Mansfield decided that:

Slavery had never been authorised by statute in England and Wales, and Lord Mansfield's decision found it also unsupported in common law. Lord Mansfield narrowly limited his judgment to the issue of whether a person, regardless of being a slave, could be removed from England against his will, and said he could not. Even this reading meant that certain property rights in chattel slaves were unsupported by common law. It is one of the most significant milestones in the abolitionist campaign.