The Russian Revolution of 1917 led not just to huge political and social change, but to a new artistic freedom. Russian avant-garde artists like Malevich, Kandinsky and Chagall flourished in the immediate aftermath of the revolution. One of their greatest supporters was art curator Nikolai Punin. Louise Hidalgo has been talking to Punin's granddaughter, Anna Kaminskaia, about how that freedom was gradually replaced with censorship and repression, and her grandfather ended his life in the Gulag.Picture: 1920 painting by Boris Mikhailovich Kustodiev (1878-1927), Bolshevik (oil on canvas), Tretyakov Gallery, Moscow, Russia