Problem: Despite long standing strategic level ambitions to increase access to continuity of carer (CoC) models in maternity services, implementation of CoC in the United Kingdom (UK) has been generally small-scale and short lived. This indicates problems in implementing and sustaining CoC as the main model of care provision, and as such a need to better understand the process of implementation itself. Aim: To use normalisation process theory (NPT) to underpin development of a conceptual implementation framework for CoC in order to improve understanding of the implementation process. Methods: Literature review on CoC implementation and NPT development and use, combined with immersion in the implementation of CoC context. Results and Discussion: A conceptual framework for the implementation of CoC is developed and individual components discussed, with a view to better understanding the implementation process for CoC models. The will of a critical mass of midwives to work in a CoC model and the provision and maintenance of the ‘organisational space’ required for CoC within the National Health Service (NHS) emerge as key barriers to mainstreaming CoC in the UK. Conclusion: There is utility in NPT as a means of understanding and conceptualising large scale implementation of CoC. With testing and further development into a practical tool, the conceptual framework developed here could become a useful aid to those involved in implementing and evaluating CoC in the context of renewed strategic direction and Governmental level support in the UK.