David has chaired many organisations in the public and voluntary sectors including currently the Royal College of Physicians, DementiaUK and Healthwatch England, and is actively involved in policy formulation in health and social care.

At the National Institute for Health and Care Excellence (NICE) David has chaired many of the National Guideline teams spanning medicine, public health social care and education, and is Special Advisor on Healthcare of the Elderly. He is a long-standing General Medical Council Visitor for Medical Education, and an advisor to the Medical Research Council. He was Chair of the Forensic Science Regulator, and undertook for the government  an Independent Review into Social Work Education, and the Croisdale-Appleby Report was published in 2014.

David is the Honorary Ambassador for the UK for the Nelson Mandela Children’s Hospital, the former South African President’s Legacy Project - the first specialist Paediatric Hospital to serve the children of the 16 nations of the Southern Africa Development Community.

David was awarded the OBE for his work for social justice, holds professorships in a wide range of academic disciplines, and holds Honorary Doctorates from more than 20 Universities for his work in health and social policy.