The man walked over and smashed the winning sculpture. Quite deliberately, then and there in the Tate Gallery. He struck it, then pushed it from the pedestal, raising his voice and, in fractured English, abusing the exhibition’s organisers. It was March 16, 1953, in the first week of an international art prize honouring victims of political oppression. Alarmed visitors pulled the angry foreigner back from the exhibit, then attendants took charge, and someone hailed a London bobby who was outside on the chilly street. So there they were, all talking away amidst the modern sculptures, with one in pieces on…