A new year brings the traditional political punch-up over the National Health Service. In the red corner, Gordon Brown is organising an “NHS constitution”, which will tell prospective patients that they must make various health commitments before they are allowed NHS treatment, and a new “screening programme”, which he says will save thousands of lives. In the blue corner, David Cameron has decided that hospitals should be financially penalised for infecting patients with MRSA or for procedures that bring poor results.

Each of these proposals illustrates just how little politicians understand about health and just how well-insulated they are from the sweaty frontline that delivers medical care. Let me explain.