A fortnightly magazine of the arts Introduced by Huw Wheldon Tonight's programme includes: The Marks of Violence A study of violence in the arts introduced by Dr. Alex Comfort. Violence of subject matter and style seems to be a hallmark of much modern art. Is this such a new departure? And what purpose does this violence serve - indulgence, protest, or simply a mirror of the times? With John Arden, Reg Butler, Ann Jellicoe, V.S. Naipaul, David Storey