The Second Special Commission reviewing the operation of the Hague Child Abduction Convention concluded that the term 'rights of custody' in Article 3 of the Convention has a 'Convention autonomous meaning' rather than a meaning dependent on the law of any one particular Contracting State. English Convention jurisprudence has developed the concept of inchoate rights that constitute Convention 'rights of custody' where a person without legal rights is caring for a child in the absence of the parent with those legal rights. These inchoate rights have not been extended to unmarried fathers sharing the day-to-day de facto care of their children. This article considers the development of these inchoate rights against the background of an autonomous Convention meaning.