One of the greatest shocks the old can deliver is to confer their approval on the new. Robert Hughes, who will be 68 this month and has been in the wars, was in no mood to shock us like this on Saturday night. In The New Shock of the New (3 July, 9.05pm), a grouchy, one-off follow-up to The Shock of the New, his superb BBC2 series on modernism 25 years ago, he surveyed the art of the years that had followed and found it wanting. Hughes dished praise only upon those practitioners who were approaching or had reached old age themselves: Paula Rego, Anselm Kiefer, David Hockney and Sean Scully, artists who keep alive the traditions of, respectively, narrative painting, political engagement, figurative technique and numinous abstraction. The man who taught us to embrace Picasso and Braque clung to the rock of the OAP.
But Hughes had always believed we were at the fag end of a good run. In the first of the original series, now being repeated on BBC4 on Thursdays, the 48-year-old Hughes, in stripy shirts and floppy hair, confidently predicted that modern art had begun in 1880 and had ended by 1980. But what a century it had been! Despite his programme's clever title, Hughes's aim had not been so much to recall the shock that the new art had caused as to explain how it had itself been a reaction to the shocking new age mankind found itself in, a mechanical, industrial, democratic age, visually dominated by still and moving photography. In such confusing days, the avant-garde believed that art "in the most disinterested and noble way, could find the necessary metaphors by which a radically changing culture could be explained to its inhabitants". It resulted in "some of the most challenging, beautiful and intelligent works of art that have ever been made, alongside a great deal of superfluity and rubbish".
Since 1980, he told us on Saturday, the superfluity and rubbish had taken over, seducing even the art market with its vulgar demands for attention. The artist's supreme purpose was now to be noticed, although this was getting harder, as newness by itself was not only no longer shocking, but museum policy. In their ignorance, the new artists frequently failed even to be very new. "Shit, man," cried Hughes before a garish mural at the Whitney Biennale in New York, "this is what they used to do in Notting Hill in 1964!" It was as if, he sighed, western art had begun with Andy Warhol.
He implied, however, there was so much that modern art could tackle if only it could raise its game. Just as the original Shock began with pictures of the Eiffel Tower, that icon of the new mechanical spirit, so did this programme, but it was now juxtaposed with film of the fall of the twin towers. Hughes did not directly ask why art had failed to address this disaster but he did wonder how Turner would have painted the H-bomb's mushroom cloud, how Goya would have depicted Belsen or David the assassination of Kennedy. The last important artistic statement about war was, he noted, Picasso's Guernica.
Damien Hirst had refused to allow Hughes to film his work, far less interview him. Less wisely, given Hughes's previous dismissal of his "porcelain inanities", Jeff Koons welcomed him in and so found himself smugly talking the critic through his Woman in Bath Tub, in which a half-decapitated Playboy Playmate grasps her breasts in horror as a snorkel surfaces before her at bathtime. Koons, nattily dressed in a suit and tie, enthused away about the relationship between cultural guilt and masturbation. During this embarrassment, Hughes was icily polite, saving his put-downs for the voice-over. (Personally, I preferred the icy politeness to the ingratiating, patronising tone he applied to his heroes - Hockney: "I've got a big project coming up." Hughes: "You've always got a big project coming up - it's called the world, mate!")
What the counsel for the defence would have argued at this point was that the Nineties art Hughes damned offers its own pleasures. It is ironic, funny, knowing and playful, qualities under-represented at the National Gallery but in superabundance at the Saatchi. You can, as Hughes does, see these works as additions to our fast-food visual culture - mind-rotting eye candy to spit out - or you can regard them as sly commentaries on it. At the least, in the context of a gallery, they give us a chance to slow down and contemplate what has happened to it. Held up, however, to Hughes's tyrannical, mystical definition that art must provide "a transcendent understanding", Hirst, Emin, Koons and company were doomed to fail dismally.
This confidently made programme (despite Hughes's injunction that art needs to slow down, the producer, James Runcie, wisely sped up the visual tempo established in Lorna Pegram's now leisurely-looking 1980 series) will, unfortunately, have given every ignoramus in town, and many more in the suburbs and shires, permission to dismiss what shocks them. It is dangerous permission to grant. It is unlikely, after all, that not one YBA has something interesting to say; and even Hughes acknowledged the melancholy power and craftsmanship of Ron Mueck's Dead Dad. But Hughes talks so well, with an Australian intellectual's gift of matching erudition with common sense, that I ended concluding he was probably 90 per cent right about 90 per cent of it.
Andrew Billen is a staff writer on the Times