This article examines United Kingdom overseas domestic worker and diplomatic domestic worker visas in place since 2012. These visas tie workers to an employer by making it unlawful for them to change employer, even when seriously exploited or abused. The article presents the findings of a qualitative study of overseas domestic workers, exploring how this vulnerable and difficult (for researchers) to reach group experience these visas in practice. Workers reported instances of exploitation and abuse by the employers with whom they arrived in the United Kingdom. Having escaped, they have become undocumented, and are trapped in ongoing cycles of exploitation. The article assesses what light this empirical exploration sheds on the question of whether the visa is contrary to the prohibition of slavery, servitude, forced and compulsory labour in article 4 of the European Convention on Human Rights and the UK Modern Slavery Act 2015.