Alan Bennett's much-anticipated The Habit of Art, now at London's National Theatre, is a rich and layered work, amusing in a gentle way, and perhaps more rewarding intellectually than emotionally, It hangs on a fictitious meeting between the poet WH Auden (Richard Griffiths) and the composer Benjamin Britten (Alex Jennings) in Oxford in 1972, when both men were nearing the end of their lives. Britten is writing a new opera based on Thomas Mann's Death in Venice and he has come to Auden for reassurance that it is a work worth pursuing.

Bennett presents this encounter through the form of a play-within-a-play called Caliban's Day, which is being rehearsed by a company of actors backstage at t[...]