…and as if to prove my own point, to myself: on Saturday morning Sal and I flew up to Edinburgh for a weekend at the fringe. Rather fortunately, we’d decided to fly from tiny toy airport London City, which meant that we could simply wander up to the security point and head straight through without any of that silly queueing nonsense we might have had to do at Heathrow. Of course we’d already conscientiously checked our explosive hair gel and deodorant into the hold, and we obediently removed our shoes so that they could pass through the X-Ray machine.

On the other side of security at City, as in most airports around the world, you are immediately confronted with the world of tat, cheap perfume, fags, and booze that is the duty free shop. There, anyone who wants them can find row upon row of glass bottles of alcohol, each with a little tag around the neck bearing the legend: “wherever you are flying today, you can take me on board”.

It’s slightly reassuring to note, I suppose, that in age when, as we are continually being reminded, we must all make compromises, capitalism bends for no man.

It’s a flawless system, obviously. I can’t think of anything dangerous that you could possibly do on a plane with a collection of glass bottles. Can you?