I had planned to chop up a DayGlo abstract painting using an axe. You might call it art criticism. I called it “making kindling”. It never happened. The painting was consigned to the log pile, judged noxious and unsaleable by my mother, inheritor of a modest art collection. A visiting dealer spotted the painting at The Matriarch’s pad before I could do the “Here’s Johnny!” thing. Shortly after, he sold it on commission to a collector for a few thousand pounds.

The dealer, an expert on lesser-known British modernists, thought the picture was worth money. As a result, someone else did too. Art, lacking practical utility, can be either worthless or priceless. The opinion of industry insiders crucially underpins both designations and all price points in between. This is particularly true for modern art, in which verisimilitude has been largely jettisoned as a criterion of excellence in response to its cheapening by photography. The power of experts to confer value reaches its zenith in the contemporary art market, the stomping ground of such former enfants terribles as Damian Hirst and Jeff Koons. Here, expert validation counterbalances the ability of living artists to expand supply.