"Popular in our time, unpopular in his. So runs the stereotype of rejected genius."

About artists he admired, like Lucian Freud, he cast the stakes in nothing less than heroic terms. “Every inch of the surface has to be won,” he wrote of Freud’s canvases in The Guardian in 2004, “must be argued through, bears the traces of curiosity and inquisition — above all, takes nothing for granted and demands active engagement from the viewer as its right.”

“Nothing of this kind happens with Warhol, or Gilbert and George, or any of the other image-scavengers and recyclers who infest the wretchedly stylish woods of an already decayed, pulped-out postmodernism.”

With a few exceptions (Roman busts, Fayumic coffin likenesses), portraiture in art's long span is quite a new--well, newish--form. It really gets under way in 15th century Italy. It came with problems, though. Portraiture as we know it is the art of making recognizable likenesses of individuals. But not all Renaissance portraits are about verisimilitude, and even when they seem to be, their truth can't be tested because usually there are no other images of the same person to test it against.

Whether writing or broadcasting, Hughes united a formidable scholarship with an infectious enthusiasm for his subject. His style was forthright, humorous and often irreverent. At a time when much of modern art was riddled with posturing and hyperbole, Hughes fixed his gaze unwaveringly on the work of art itself, regardless of its political or social agenda.

His judgments could be merciless. Of Jeff Koons, for example, he said: “Koons is the baby to Andy Warhol’s Rosemary. He has done for narcissism what Michael Milken did for the junk bond.” The duo Gilbert and George were among the “image-scavengers and recyclers who infest the wretchedly stylish woods of an already decayed, pulped-out postmodernism”.