His main research interests are the prevention and treatment of trauma and the links between energy and health.

He established and is co-ordinating editor of the Cochrane Injuries Group, an international network of individuals that prepares and maintains systematic reviews of the effectiveness of interventions in the prevention, treatment and rehabilitation of injury.

He is principal investigator of the CRASH trials, large international randomised controlled trials that seek better ways to treat seriously injured trauma patients. The MRC CRASH trial, which included 10,000 patients with head injury from around the world, showed that corticosteroids, which were widely used in the management of head injury, did not improve patient outcome after head injury but increased the risk of death. The CRASH-2 trial has shown that tranexamic acid, an inexpensive and widely practicable treatment, safely reduces mortality in bleeding trauma patients.

He is the author with Phil Edwards of The Energy Glut: the politics of fatness in an overheating world.