Janet Street Porter and crime writer Martina Cole discuss their good reads with Harriett Gilbert. The guests talk - and vociferously disagree - over American Wife, Curtis Sittenfeld's fictionalised biography of Laura Bush, The Iron King, the first novel of Maurice Druon's 1950s series which has been hailed as 'the original Game of Thrones', and Muriel Spark's classic novel The Ballad of Peckham Rye