More than 30 years ago - in 1977, to be exact - I co-authored a book called Work and Struggle: The Painter as Witness. Its subject was one aspect of the academic painting of the late 19th and very early 20th century - art which dealt not with the comfortable lives of the rich but with all the social problems of the time. There were over 200 illustrations, most of them drawn from publications issued in conjunction with the official Salons of the period. We would have preferred to go back to the actual originals, but when we searched for these, they were largely missing.

In some cases, for example where the paintings had been dispatched straight from the Salon to some provincial French museum as an official purchase, we did contact the institution that was supposed to possess them. The answer - if we got one - was almost invariably that the work concerned was "now in no condition to be photographed". In other words, it has fallen so far out of fashion that nobody, even those who were officially responsible for its welfare, had bothered to look after it. The illustrations in the book therefore held up the mirror to an art world that had, in physical terms at least, almost completely vanished. The Modern Movement had swept it all way.