Steve Ainsworth questions the worth of public health physicians and offers us up to fill the growing gap of GPs. He makes three classic errors.

First, infectious disease is not now public health practitioners' main concern, although this is a specialist area requiring regular sophisticated surveillance and is not - as Ainsworth suggests - something which anyone (medically qualified or not) could contain. Rather, our specialty's main concern is the organisation of healthcare in its widest sense and influencing the determinants of health.

Second, the disciplines on which public health is based are wider than those of our clinical colleagues. They range from epidemiology and economics to social science. We need specialists in each area and practitioners with an understanding of them to affect the public health and advise health authorities, primary care groups or local authorities. The perspective of public health physicians is quite different to their clinical colleagues'. The skills that have been specific to our practice are now recognised by many clinicians as valuable for their practice. In response, the public health training programme in Anglia offers six-month full-time posts to specialist registrars in clinical programmes to work in a public health department, and supports GP registrars to develop academic and population health skills.

Third, the success of public health practice is measured in absence not in presence. The BSE crisis and the disparity in health between the rich and poor are but two examples.

Ainsworth is correct that public health is political. Much of our training is in understanding the political system to further the population's health, for public health is a political process where choices are made.

People who believe there are no public health problems left need look no further than the scientific evidence on the determinants of health. They should remember that public health is broad enough to involve many organisations and people. Those not part of the solution to these public health problems may be a part of the problem.

Celia Duff

Consultant in public health medicine/faculty adviser

David Pencheon

Consultant in public health medicine/programme director

Anglia