Managers and clinicians in the NHS are under growing pressure to improve and redesign services in a way that both optimises health outcomes and controls costs. There is huge potential for health services research to make a larger contribution to this process but there is a disconnect between the theory and empirical evidence underpinning how best to design and deliver high quality health services and what actually happens in practice. This has challenged policy makers, academics and front-line staff for several decades. This 30 month multi-method study builds on previous knowledge mobilisation research funded by the HS&DR programme. It aims to increase the influence of health services research on decisions about the improvement and redesign of NHS services in two key ways; firstly by substantially developing the evidence base underpinning the nature and effectiveness of co-production models of knowledge mobilisation in which researchers are embedded within NHS service settings, and secondly by co-producing practical guidance on the design and implementation of embedded models of co-production for managers and clinicians in the NHS, its academic partners and people who use services. We propose four interlinked work streams (WSs): WS1: a critical narrative review of the literature in the fields of co-production and embedded research; WS2: an environmental scan of embedded researcher initiatives across the UK, such as a sociologist evaluating an integrated care programme or an operational researcher improving patient flow in a children's unit; WS3: four in-depth qualitative case studies of NHS embedded researchers and their associated networks, activities and impacts; and WS4: a concurrent co-production and active engagement and influencing strand to ensure that the study achieves maximum impact in the NHS. Data collection and analysis will be informed throughout by methodological best practice, underpinned by the principles of co-production through engagement of stakeholders and supported by an international project advisory group. The main non-academic outputs from the project will be a range of practical tools (including training materials, detailed guidance, indicative job descriptions and person specifications) so that NHS organisations can learn about how to use embedded co-production in the most effective ways in order to improve the delivery of high quality research-informed care. We will also contribute to addressing significant gaps in the current international research literature on knowledge mobilisation. The NHS will gain the following benefits from the project: The NHS and its partner organisations that are currently using embedded co-production initiatives will be able to use evidence-based guidance, person specifications, training templates and training resources that we produce in order to optimise the effectiveness of their work and its timely impact on patient care; NHS organisations that have not yet considered models of embedded co-production will be given the resources to explore how they could use this approach to improve decisions that impact on service delivery and will be given the tools to enable them to do so rapidly; The NIHR HS&DR programme will have a better understanding of the potential benefits and risks of embedded co-production and related models of research, and how they might contribute to increasing the impact of health services research in the NHS.