Professor Suzannah Lipscomb talks to Laura Cumming - author and art critic for The Observer - about Velázquez, arguably the greatest genius of Spanish painting. They particularly discuss one of the world's most remarkable paintings - Las Meninas ('The Ladies in Waiting'), how the artist rose through the stifling, gilded court of Philip IV, and the way in which Velázquez dignified everyone he painted - from the King himself through to some of the most vulnerable members of his court.