Seriously – Mr Hirst – I am talking to you.

But here is the other side of the story: an artist so wealthy and powerful that he can kid himself he is an Old Master and have the art world go along with the fantasy. The most recent paintings here were finished this year, so the fantasy is still very much alive. So is the courtiers' chorus of support. The exquisitely produced catalogue has an essay by a senior curator at the Prado in Madrid, who draws comparisons with Caravaggio and Velázquez. Yikes. It would be impressive stuff if we did not have the paltry reality of Hirst's paintings before our eyes. At White Cube, I pass from picture to picture, trying not to crack up laughing or actually swear out loud. The exercise feels like a parody of being an art critic, for these are humourless parodies of paintings. Like the Prado expert I can spot the analogies – lemons, how Zurbarán – but they work only to destroy and humiliate Hirst's daubs. Seriously – Mr Hirst – I am talking to you. It seems you have no one around you to say this: stop, now. Shut up the shed. I say this as a longtime admirer, not an enemy. No encounter with a contemporary work of art has ever thrilled me like the day I walked into the Saatchi Gallery in 1992 and saw a tiger shark's maw lurch towards me. But these paintings are abominations unto the lord of Art. They dismantle themselves. Each of these paintings – from the parrot in a cage to the blossoms and butterflies – takes on the difficulties of representational painting and visibly fails to come close, not merely to mastery, but to basic competence.