Can workplace industrial democracy be a tool of transformative working-class empowerment in the contemporary context of liberalised industrial relations? We argue that in the presence of specific historical legacies and organisational circumstances, radical forms of workplace industrial democracy can contribute to the strengthening of workers' structural, associational, societal and ideational power resources, even under hostile conditions of labour-capital balance of power. After providing a conceptual definition of radical industrial democracy, we develop our argument by showing its workings in practice in a salient case of industrial restructuring, that of the former GKN plant in Florence, Italy. Since summer 2021, GKN workers have undertaken a long-lasting mobilisation against the plant closure and for its reindustrialisation, in the perspective of a productive reconversion compatible with the concept of just transition. We show how the practices of radical industrial democracy embedded in the GKN plant played a key role in shoring up workers' power resources, supporting the long-lasting mobilisation and the convergence with other social movements. Our findings underscore that radical industrial democracy can be a key asset to cultivate autonomous working-class power. It needs, however, to be backed up by broader institutional and political infrastructures to lead to transformative outcomes.