The article explores how the British Caribbean turned into an unlikely refuge for intercolonial escapees from slavery in the 1820s and 1830s. During this period, hundreds of enslaved men and women fled from French, Danish, and Dutch Caribbean colonies into British territories and entered in intense, and often contentious, encounters with low-ranking officials on the ground. The article examines how these individuals made use of legal ambiguities and loopholes in British slave trade abolition, thereby resetting, reinterpreting, and broadening the meaning and scope of freedom granted under it. The consequences of their actions were far-reaching and often uncontrollable, as they carved out a legal grey zone that created, in practice, a quasi-free-soil sanctuary in the heart of Britain’s planation complex. For more than a decade, local assemblies and officials, legal experts, British and foreign planters and their lobbies, foreign diplomats and British politicians grappled to close this grey zone. As it reincorporates enslaved fugitives in the history of state-sponsored antislavery, the article also shows how the case of these fugitives triggered a fierce debate about the essential parameters of imperial governance around 1800. This debate involved the renegotiation of the boundaries of freedom and slavery, and of subjecthood and (un)belonging. It gave rise to crucial questions related to imperial governance, including the scope of executive power and the challenge of coordinating imperial and colonial law as part of one coherent legal space. Because it involved other empires, the fugitives’ case also highlighted the connections between antislavery, sovereignty, and inter-state law.