The NHS has transformed medicine and improved lives.1 But the ageing population along with the burden of non-communicable, mental, and neurological diseases have put its financial viability and sustainability into question. The next decade is projected to be the most financially austere in NHS history,2 even if recent pledges materialise. Reorienting the NHS to invest in cost effective disease prevention is essential if the health system is to be sustained. Disease prevention has four key benefits that show how cost effective it is both in and beyond the health and social care system (fig 1). We focus on the role of the NHS in disease prevention and the role of cross government agencies in tackling the wider determinants of health.