Mark is the Director of Research and Training at the Newcastle Cognitive and Behavioural Therapies Centre and Honorary Professor of Clinical Psychology at the University of Durham. He is also Professor of Clinical Psychology at the University of Newcastle. He divides his time between NHS duties, where he directs the Newcastle Diploma in Cognitive Therapy, and the University of Newcastle. He has published over 80 papers, mainly in the field of intrusive thoughts and worry and on the formulation and treatment of Obsessive Compulsive Disorder and Generalized Anxiety Disorder. He regularly provides workshops on the cognitive behavioural treatment of these disorders. He chaired the Guideline Development Group for Obsessive Compulsive Disorder (OCD) and Body Dysmorphic Disorder for the National Institute of Clinical Excellence (NICE) from 2003 to 2005.