In the Musée d'Orsay in Paris hang the revolutionary works of painters who made art modern in France more than a century ago. Here they are, the true greats of early modernism: Cézanne and Van Gogh, as well as Gauguin and Degas, Monet and, of course, Seurat. That's six, and there are obviously several more profoundly important figures in France at that time, including Toulouse-Lautrec and Odilon Redon. That makes eight. And there are more, too, including sculptors led by Rodin. Perhaps you could bring the figure up to 16, even 20, without scraping the barrel.

Say we agree, generously, that 20 artists genuinely mattered in late 19th-century France at the dawn of modernism, one of the truly great moments of art history. Now, how many living British artists are regarded as important, unmissable, revolutionary? To judge from the bonanza of 21st-century British art touted in newspaper articles, art fairs, group shows, magazines and a host of solo shows at legions of galleries, there must be – what? – a hundred, no, more like two hundred names to conjure with.

So this must be the greatest moment ever in the story of art, a cultural golden age to put fifth-century Athens to shame.

Or could 21st-century British art possibly be overhyped?

Come on – do the sums – they don't add up. The young and middle-aged artists celebrated in Britain today cannot all be marvellous. Just as Britain's economy in recent times turned out to be running on false credit, so too our art scene has ballooned into a mass delusion.