Due to the changing demographics of societies around the world, ageing has become a major concern for governments and policy makers alike. What has also become clear is that the older adult consumer group and the factors affecting this age group have been studied relatively less in the literature. In this paper, we aim to investigate the adoption, usage, and diffusion of smartphones within the UK older adults so as to identify the factors encouraging or inhibiting smartphone usage and service provision within this age group. To this end, we propose a conceptual framework (Model of Smartphone Acceptance) based on a set of well-known theories of adoption and diffusion. We collected data from 984 participants living in north London and applied the Partial Least Square Structural Equation Modelling (PLS-SEM) technique to analyse the data. Our research can contribute towards reducing some of the existing digital divide within UK older adults. Moreover, businesses can benefit from our research by understanding the significant factors affecting the adoption of smartphones among the UK older population and to adapt their policies accordingly.