Slavery had never been authorized 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 their will, and said they 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.

Some historians believe the case contributed to increasing colonial support for separatism in the Thirteen Colonies of British North America, by parties on both sides of the slavery question who wanted to establish independent government and law.[3] The southern colonies wanted to protect slavery and expanded their territory dramatically in the decades after independence was won.[4][5]

Probably started this country too. JFC