The involvement of patients and the public in the development of clinical research initiatives in the UK has been central and is increasing. Whilst initially developed in relation to cancer research and cancer care, this activity has now generalized to all of healthcare research particularly through organizations such as INVOLVE (www.invo.org.uk). Patients and Public Involvement (PPI) has been evaluated and shown to be established across the NHS in the UK. The National Institute for Health Research in England has made PPI central in its development. More recently evidence is accumulating that PPI has significant impact on the quality and delivery of clinical research in healthcare but more work on the evaluation of its impact is required.