The sugar tax is obviously a very sensible idea but it’s much more than that. It’s prophetic, it’s a sign of a major change, it’s the swallow that could be heralding a medical summer. The tax is shorthand for a long running battle around what is a healthy diet, which turns out to be about a lot more than just diet.

It’s generally agreed that the NHS is not in good health but there’s no clear diagnosis. There are plenty of suggestions – lack of funding, uncompassionate nurses or box-ticking managers. But I want to suggest another one: the crisis in evidence based medicine (EBM).