He warns that increasing the role of the private sector in the NHS, as the British government is now doing, is risky. "I would be cautious – very cautious," he said. "When you invite entrepreneurial private sector investors into the delivery of care, under most payment systems, they will be very interested in volume. They will be very interested in doing more things to people and you may find that you lose control of that level of discipline to the disadvantage of patients. When more things are done, more unnecessary things get done and more hazard enters the system – not just cost.