Neither the poet W.H. Auden nor composer Benjamin Britten were exactly famous for knockabout comedy. The surprise of Alan Bennett’s new fictionalized bio-drama about their tussles between reputation and sexuality is the high laugh count. As befits a play set during rehearsals, most are theatrical in-jokes. As Fitz, the actor playing Auden, Richard Griffiths muses on his manners: “Look at him, they say in the canteen, there is an actor who has never brought in a cake.” But the loudest sound in “The Habit of Art” is that of its author having his cake and eating it.

On designer Bob Crowley’s recreation of an anodyne National Theater rehearsal room, a company gathers midway through rehearsals of a new play about the two artists. With the director absent at a conference (comic dig at helmer Nicholas Hytner, whose other job is running the National), beady stage manager Kay (Frances de la Tour at her long-suffering best) leads a run-through.

The frame of amusingly sour rehearsal-room behaviour — ego problems, squabbles with the writer (nicely touchy Elliot Levey) — provides entertaining, if unoriginal, flummery. Yet the play-within-a-play device feels like a get-out clause, a hoary device to overcome a central problem in the handling of subject matter identified within moments of the rehearsal starting.

Adrian Scarborough plays Humphrey Carpenter, a reporter who went on to write biographies of both Auden and Britten. He visits elderly Auden, now ensconced as Professor of Poetry at Oxford University. Auden, who is actually expecting a rent boy (sparky Stephen Wight), is on typically testy form: “Why poets should be interviewed I can’t think. A writer is not a man of action.” True enough — but that lack of action throughout “The Habit of Art,” with Carpenter weakly providing voiceover-like narration, proves to be a stumbling block.

At its core, this is another “When X met Y” discussion piece that imagines a reunion between Auden and Britten, who famously worked well together early in their careers but fell out in 1942 and never spoke again.

Britten, who developed a nasty, lifelong habit of ditching people, is believed to have split with Auden because he was stung by a letter the poet sent in January of that year. Although both were gay artists at a time that necessitated being closeted, their perspectives upon their sexual desires were wildly opposed. In his letter, Auden upbraided the composer for his need of love and approval and his attraction to bourgeois convention.

Bennett’s play springs from the fact Britten wrestled with those very issues (none too successfully) while writing his final opera, “Death in Venice.” Thus we see Alex Jennings’ upstanding, buttoned-down Britten visiting Auden because he craves his approval for the project.

Their often witty but increasingly passionate debates about the private impulses behind public work, the importance/impertinence of biography and, crucially, the seductions (in every sense) of outward success form the play’s core.

Much of the tension derives from unmissable autobiographical resonances. Bennett only publicly addressed his homosexuality very late in life, a matter of fascination to his vast British audience that regularly keeps his volumes of published diaries at the top of bestseller lists. Furthermore, the debates speak clearly to Bennett’s discomfort about his own status as a “national treasure.”

Yet the taut atmosphere at crunch points reveals how slackly meandering things are elsewhere.

The structure also creates a conundrum. In the rehearsal sequences, Hytner encourages the actors to indicate — sidelong glances, raised eyebrows, etc. — just how bad they think some of the fictional playwright’s wilder fancies are. Given that they play talking furniture, they have a point. But although poking fun at playwrights provides laughs, if the play is supposedly ridiculous, why should we take it seriously? It looks like a weak excuse for poor dramaturgy.

What it indicates is that Bennett is mostly stronger on set-pieces than sustained drama, putting the play in grave danger of slipping into an almost revue-like succession of cozy snapshots. In a work that openly inveighs against the perils of being too cozy, that’s a problem.

Griffiths stepped in to replace Michael Gambon when he was forced to quit due to ill health. Griffiths’ benign presence helped steer Bennett’s “The History Boys” to triumph, but that quality is less helpful for the more mulish, irascible Auden, and he lacks danger and unpredictability. It’s by no means solely the actor’s fault, however, that the play gradually moves into sentimentality, notably in a paean to playwriting in one of the (too) many false endings — a structural misstep that indicates a writer uncertain of exactly what he wishes to say.

Bennett’s reputation alone has already sold out the initial National run, and the play is the next presentation to be filmed for the NT Live season. But unlike “The History Boys” which welcomed all comers, not least in the U.S., audiences may baulk at what could be seen as insider-dealing. The most frustrating element of “Habit” is that beneath all its playfulness, there’s a shorter, tighter, tougher play struggling to get out.

The Habit of Art

National Theater/Lyttelton, London; 898 seats; £42.50 $71 top

  • Production: A National Theater presentation of a play in two acts by Alan Bennett. Directed by Nicholas Hytner.
  • Crew: Sets and costumes, Bob Crowley; lighting, Mark Henderson; original music, Matthew Scott; sound, Paul Groothuis; production stage manager, David Marsland. Opened, reviewed Nov. 17, 2009. Running time: 2 HOURS, 25 MIN.
  • Cast: Fitz, W.H. Auden - Richard Griffiths Henry, Benjamin Britten - Alex Jennings Donald, Humphrey Carpenter - Adrian Scarborough Tim, Stuart - Stephen Wight Kay - Frances de la Tour Author - Elliot Levey With: John Heffernan, Laurence Belcher, Otto Farrant, Toby Graham, Tom Attwood, Martin Chamberlain, Philip Childs, Barbara Kirby.