A new exhibition charts Picasso's influence on British artists from Wyndham Lewis to David Hockney. But who were the painter's oustanding collectors and advocates?"I came to the conclusion that he is probably one of the greatest geniuses that has ever lived." This remarkable sentence about Picasso comes from a private letter of early 1914. It was written by Vanessa Bell shortly after she had visited Picasso's studio in Paris and seen not only early works but his recent collages and relief constructions which were among the most innovative and influential works of art then being made.In assessing her comments we have to remember that she was not writing of the Picasso we now know, not even of the celebrated figure from ...