Firewalls are clear divisions between border policing and the provision of basic social rights. They have a dual character: to ensure that no information collected with the purpose of safeguarding basic social rights should be shared for immigration control purposes; and that migrants should not be subject to immigration control when being present at, or in the vicinity, of religious, private and public institutions upholding and providing social rights. This article suggests a normative argument for ‘firewalls’ in the context of social work and develops the concept theoretically as a principle practised and negotiated at different scales.