As John Le Carre 's novel The Constant Gardener is released as a film tomorrow, the writer talks to James Naughtie about conspiracy theories and global politics. Plus, from sculptor Rachel Whiteread , the latest installation for Tate Modern's Turbine Hall; the search for Britain's best city for music; director Todd Solondz on photographer Diane Arbus 's bizarre vision; the boom in guides to modern etiquette; and Britain's new ballet capital - Birmingham. With Verity Sharp. Series producer Julian Birkett ; Executive producer Edward Morgan www.bbc.co.uk/cultureshow