Previous literature has demonstrated that networks can be valuable sources of professional learning. In 2005 all Liverpool schools formed into ten Learning Networks with the aim of improving the quality, and entitlement of, continuing professional development (CPD) for staff as part of a whole-scale local authority initiative. The Liverpool Learning Networks Research explored professionals' CPD experiences following this organizational change and whether it has enhanced their practice. Triangulated data, a large-scale survey and qualitative interviews conducted in 2007, seem to suggest that where professionals benefited from professional learning in a networked context, the quality of the networked CPD as well as a positive school culture and intra-school collaboration were all important contributors to the success of networked-CPD. This finding can usefully apply Turbill's ("Teacher learning for educational change." Open University Press, Buckingham, 94-114, 2002) model of professional learning to the intersection between school-based and networked-CPD, which suggests that it is at this intersection between internal and external domains that teacher learning can take place. Two scenarios, where this interplay between school-based and networked CPD is positive (enhancement) or negative (tension), are reported through five case studies of professionals underpinned by the survey data, where relevant.