Medicine, over the past fifty years, has metamorphosed from a modest pursuit of limited effectiveness into a massive global phenomenon employing millions and costing hundreds of billions. Now, in the vast shiny palaces that modern hospitals have become, previously unimaginable goals such as transplanting organs have become routine, while every year tens of thousands doomed to blindness from cataracts or immobility from crippling arthritis have their sight and movement restored. Medicine has become the most visible example of the fulfilment of the great enlightenment project in which scientific progress vanquishes the twin evils of ignorance and suffering for the benefit of all.

So medicine works – with one obvious glaring exception: the treatment of cancer. To be sure, some forms – such as the leukaemias and lymphomas that affect children – are curable with a combination of radiotherapy and chemotherapy, but for the vast majority the comment more than twenty years ago