You rightly point to the triumph that ageing represents and the importance of focusing on the prevention of ill-health in later life (Editorial, 18 August). The emphasis should be on extending healthy life expectancy – the number of years that people live in reasonably good health. But in contrast to other European countries, the average healthy life expectancy in the UK is falling, but with wide inequalities between different places and groups. For example, women on the Orkney Islands live an average of 20 more years of healthy life than those in Blackpool (75 v 55 years). Such stark inequities reveal that it is not medicine or health systems that determine how people age, but the social and commercial determinants of health – the circumstances in which we are born, live, work and age – the realm of public health. These factors contribute as much as 60% of the variations in health in later life. Addressing these wider determinants of health requires a cultural revolution in policymaking: health equity in all policies, a life course focus and the three Ps (prevention, prevention, prevention). In essence, this was advocated in the 1970s by the then secretary of state for social services Barbara Castle, but never enacted. Perversely, as Michael Marmot has shown, under the Tory austerity regime, public health budgets were cut substantially. Restoring them is vital if Labour is to achieve its mission to halve the gap in healthy life expectancy between the richest and poorest regions. Alan Walker Professor of social policy and social gerontology, University of Sheffield