We spend more on health care than ever before but people are now far more likely to fall ill than they were a generation ago.

A major survey showed that today 95% of the population are ill at least once a fortnight. The commonest illnesses are coughs, colds, sore throats, sinus troubles and chest infections. The biggest and healthiest industry in the world is the one which makes and markets pills and potions designed to help us stay well and get better when we fall ill.

Infectious diseases are commoner today than at any time in living memory: diseases as varied as pneumonia and tuberculosis are becoming commoner and are killing more people than they did a decade ago. But they are not the only cause of death and serious illness to be on the rise. And they are not the only cause of death and serious illness to be rising because of damaged immune systems. Our susceptibility to cancer is also increasing as our immune systems become weaker.