Now, though, if you descend 30 metres below the Strand to the murky innards of a disused Tube station, you will find that the Underground has been commandeered for somewhat less gloomy considerations. A collaboration between the writer John Berger and Theatre de Complicite director, Simon McBurney, The Vertical Line takes you on an imaginary journey backwards in time and downwards in space to the Chauvet cave in France. It was here, in 1995, that paintings of animals were discovered which, dating back 32,000 years, constitute the oldest images created by man yet found.
A spooky combination of intrepid potholing and reverberating meditations on time and art, this powerful experience begins with saturation bombardment by images flashed up on a bank of television screens and ends in a tunnel of palpably dense darkness where we join in the attempt to recapture what it was like to discover these ur-paintings, collapsing the concepts of "then" and "now".
In between, the journey takes in a huge circular shaft where ghostly images of Berger lecturing on the astonishingly well preserved and life- like Egyptian funerary portraits from Fayum are projected on the bleak walls. It also includes an episode where you lie on mattresses by a defunct line and look up at lonely cloudscapes shifting across the barrel vaulting while Berger, aping the tones of a foreign correspondent, offers a front- line report on Corsica 3,000 BC.
The main philosophical point would seem to be that it is naive to call the art of cave painting "primitive". "There was no fumbling at the beginning," declares Berger. "The need to make images did not precede the talent for doing so." Allied to this assertion is the more difficult and tendentious notion that what gives the Sayum portraits and the animal paintings their special power is that the artists submitted to being looked at by their subjects: hence, the pictures are, in a curious way, self-portraits. The five remaining shows are, alas, fully booked. But the curious can follow the event on the Internet at www.innercity.demon.co.uk. A piquant conjunction of the ancient and modern.