Civil rights organisations and critical social research demonstrate that, within advanced democratic states, economic marginalisation and political exclusion – institutionalised and manifested in structural relations of classism, racism and sexism – underpin systemic criminalisation and incarceration. They reveal that prisoners endure egregious rights violations, restricted regimes and minimal opportunities for rehabilitation. In ‘advanced’ democracies children’s incarceration amounts to what has been described as a ‘cradle-to-prison pipeline’. This article focuses specifically on the incarceration of under-18s, arguing that a current fault line is commitment to penal reformism, what Angela Davis terms ‘the amelioration of prison practice’, rather than abolition of custodial facilities. It interrogates tensions between the realities of incarceration and penal reformism concerning child custody. Focusing on the diversity of incarceration across UK jurisdictions, it considers the climate and consequences of punitive responses to children’s law-breaking and behaviour labelled ‘anti-social’ in the context of internationally agreed children’s rights standards. This is followed by a review of literature theorising the ‘dichotomous relationship’ of penal reform in a climate of punitivity. Advocating the abolition of incarceration, the article concludes with a discussion of decriminalisation and decarceration in the context of children’s rights; promoting community-based alternatives and use of welfare-oriented secure accommodation solely to protect a child or others from immediate harm.