If Alan Bennett had written a play about W.H. Auden and Benjamin Britten we would probably have welcomed it and slipped easily into suspending disbelief, into relishing his version of the great men. But Bennett has mischievously frustrated expectations by writing a play about writing a play about Auden and Britten. What we see is a chaotic rehearsal attempting to get the fictitious play on its feet. So Bennett both demystifies and celebrates the creative process. It’s a rich, meditative work, endlessly witty and yet ultimately sad. It ponders sex, death and biography, but in the end it feels like a poignant eulogy to art and the messy craft of making art.

The internal play is set in 1972, when Auden returned to Oxford to live in notorious squalor, and imagines an encounter between the poet and his one-time collaborator. Britten is struggling with his new opera, Death in Venice. Waiting in the wings is Humphrey Carpenter, who will later write biographies of both men. Both plays, the actual and the fictitious, examine the ethics of biography; both consider the way art can conceal or reveal its creator. And the interplay between the two is a part of this. Playfully, Bennett has his cake and eats it, getting his onstage author, rather than himself, to rummage around in Auden’s unsavoury habits. More seriously, his complex structure encourages speculation as to how much of himself he is revealing, and when.

The downside is that the play itself is too cerebral, self-referential and frustrating: you want to get close to the subject and can’t. But that is partly the point. And there is much fun to be had with the Pirandellian structure. Even while coining jokes at actors’ expense, Bennett celebrates their skill, obliging his cast to slip between two levels of characterisation. Richard Griffiths, as Auden, and Alex Jennings, as Britten, handle this beautifully, and are superb in their crucial encounter.

Nicholas Hytner’s droll staging on Bob Crowley’s admirably cluttered set is full of enjoyable performances, particularly Frances de la Tour as a beleaguered stage manager, John Heffernan as her enthusiastic deputy and Adrian Scarborough as a disconsolate actor. And Bennett finally, movingly, reminds us that everyone in the theatre has the habit of art: a hard habit to shake.

Tel +44 20 7452 3000