It is with heavy heart that I report that a good 20 percent to 30 percent of 20th-century paintings up for sale these days online and at certain provincial auction houses are “trappers” (shorthand for cheese in the trap). This is a term I have coined by necessity for works that cleverly “suggest” themselves as the work of recognized artists but not cataloged as such — paintings purportedly by people like Jack Vettriano, Augustus John or Francis Bacon, placed in oldish frames, and often with fake exhibitions labels on the back. They are sold as by “unknown artists” and priced with tantalizingly low estimates in the hope of getting two rival bidders, thinking they are onto a winner, to fight it out. The vendors normally disappear into dust when you try to track them down, but could be anybody from the faker himself, an intermediary or even the auctioneer.

I bought one of these, a putative Picasso representing four abstract reclining nudes, for £120 at auction earlier this year (for research purposes only I might add) and had it resting on the floor of my West End gallery in London for a couple of weeks before I took it home. How depressing is this? One of my better clients spied it on the ground among the Van Dycks, Gainsboroughs and Sir Thomas Lawrences and drawn by the zeitgeist ruggedness of the forms, turned to me and said, “God I love this stuff. So pleased you are getting in to it.”