According to the World Health Organisation, health is not merely the absence of disease but the presence of complete social, psychological and physical wellbeing….

The problem with the WHO’s definition, of course, is that to deny anything that anyone desires is, likewise, potentially in contradiction with the system’s founding principles. If I pine for an expensive car that will improve my social status, and if social status (as it has been suggested) is a determinant of health, then it follows that I should be prescribed that car by my doctor on the grounds of health.

Impotence may be caused either physically or psychologically. A man may fail to desire any longer the woman he happens to be with; these things happen. Should, then, the NHS provide the man with someone whom he does desire, by setting up a call-girl service?

Lines have to be drawn somewhere, of course, but unfortunately the world is not divided into nice neat categories for the convenience of line-drawers. Almost all phenomena of any importance occur on a continuum, and so where to draw the line has long been a matter of judgment rather than of discerning clear, natural demarcations.