Alan Bennetts play The Habit of Art, first performed at the National Theatre in 2009, is a play within a play. The stage is set as a seedy rehearsal room with the principal players having a run through with the director absent, the writer present and the assistant stage manager filling in for two actors who are tied up somewhere in a matinee. Ostensibly, the drama being rehearsed is about a fictional meeting between the poet, W H Auden and the composer Benjamin Britten. However, it becomes a discussion about writing, acting and the exploitation of rent boys. This is not an easy play to perform, everyone is cast in several roles and the great trap is that the cast, when they are playing the players will start acting, ACTING. Sadly, there is too much of that in this production, directed by Philip Franks, for the play to be as enjoyable as it might be. There is a huge amount of wit in it and David Yelland, who plays Britten, gives a natural performance with wonderfully light comic timing. He is a recognisable character. Sadly, we dont see enough of Yelland in the play and certainly not in the first half. Alexandra Guelff, as the assistant stage manager stepping in for multiple roles, is also a delight. I loved her American woman, channelling Katherine Hepburn. Matthew Kelly who plays a big, blundering, bombastic Auden, is the centrepiece of the play. This is a difficult character to get the audience to empathise with. Hes a disgusting old man who pees in the sink, deliberately soils his trousers and hires rent boys. He has great lines but Kelly doesnt make us like him enough to laugh at them. In the story, Britten has come to see Auden to get reassurance that he should continue composing his opera Death in Venice, based on the book by Thomas Mann. Britten is concerned that the central character, the writer Gustav von Aschenbach, falls in love with a 14-year-old boy. He is worried that this comes too close to his own proclivaties. He wants Auden to tell him, not to worry, carry on with the music. This is a brave play. Its disturbing. Bennett is asking what is is like to be a rent boy. It takes subtle performances to turn this into entertainment.Too many turns here are self-conscious when what is needed is something from the heart. The Habit of Art is at Cambridge Arts Theatre until Saturday, November 3.