Imagine if a team of scientists devised a drug which massively reduced people’s chances of developing cancer or heart disease, cutting their overall likelihood of dying early by 40%. This would be front page news worldwide, a Nobel prize as good as in the post.

That drug is already here, albeit administered in a slightly different way: it’s called cycling to work. One of the more puzzling political questions is why it is so rarely prescribed on a population-wide level.

Most people recognise riding a bike makes you more healthy. But studies have shown the impact of even a relatively modest regular cycle can have near-miraculous health dividends.

There is a credible argument that encouraging bike use to Dutch or Danish levels could do more than perhaps any other single intervention to save the NHS from collapse. It could even greatly mitigate the crisis in adult social care.

This might sound far-fetched, but consider the evidence. At the heart of the issue is what public health experts routinely describe as a pandemic of preventable illness connected to physical inactivity.