After watching a theatrical story build inexorably, it’s usually more than galling to be left with an ambiguous ending. Simon Gray’s “The Late Middle Classes” makes such ambiguity engrossing. David Leveaux’s exquisitely judged, beautifully acted production turns a neglected play into a quiet English masterpiece of slow-burn tension. The structure is a cunning exercise in misdirection: From the opening scene in which middle-aged Holly (Peter Sullivan) visits his childhood piano teacher Mr. Brownlow (Robert Glenister) with questions about a memory loss, the odor of suspicion grows and envelops the audience.

With the action promptly cutting back to the past, the play’s momentum is governed by the implied promise of revealing exactly what happened between them. Yet this is not another recovered-memory drama. As becomes ever clearer, Gray’s real point of concentration is something more complex than individual facts. His eyes are fixed on the repressive, suffocating circumstances that bred them, an idea made legible by the back wall of Mike Britton’s simple design, which smothers the artifacts of a home in chintz.

The clue is in the title: Gray is writing about middle-class England in the early 1950s, the strained postwar era of rationing not only foodstuffs but of openly expressed emotion.

Ten-year-old Holly (serious, reserved Harvey Allpress at the performance reviewed) lives on an island off the south coast, a sort of mini-England, a small place filled, to the horror of his mother Celia (deliciously brittle Helen McCrory), with small-minded people. His father (Sullivan) has status as the island’s pathologist, but Celia yearns for the possibilities of London. One way out would be for Holly to win a scholarship to a London school, but that necessitates sticking with the private piano lessons that are making him uneasy.

Despite its more contemporary subject matter of suspected pedophilia, in all other respects, this is territory famously mined by Terence Rattigan (“The Deep Blue Sea”) and Noel Coward (“Brief Encounter”), but Gray has the benefit of perspective. His play, written in 1999 but never seen in London, is wittier and more waspish about the period. Celia’s first entrance couldn’t be more knowing: She’s in tennis whites, the defining image of country sophistication.

Ironically, McCrory goes to town with Celia’s boredom, her seemingly artless physicality as artfully contrived as her drop-dead diction. She seizes the potential of Leveaux’s measured pacing, filling the stage time — often hilariously — with her character’s needs. Armed with Gray’s compassion, she makes Celia simultaneously selfish and sympathetic.

As her buttoned-down husband, Charles, Sullivan has the harder job. He, too, finds laugh-out-loud comedy, as when he skirts elaborately around while passing the facts of life on to his embarrassed son, but he’s still more impressive showing the anger and hurt boiling beneath the ruthlessly stiff-upper-lip surface.

Sullivan’s powerful suggestiveness is emblematic of Leveaux’s production. As the Austrian emigre piano teacher, Robert Glenister appears to physically glow. What’s never quite certain is whether that glow comes from his zealous pride in his pupil, the burning of guilty passion or defiance. Similarly, as his fearful Viennese mother, Eleanor Bron shimmers on a knife-edge of knowledge, hope and doubt. Does her fear of “more trouble” stem from being a foreigner or her son’s activities?

Leveaux’s quasi-thriller tone sustains an underlying sense of dread. While conspiracies of silence and “good manners” are revealed to have been damaging, in this case they are never less than dramatic.

The Late Middle Classes

Donmar Warehouse, London; 249 seats; £29 top

  • Production: A Donmar Warehouse presentation of a play in two acts by Simon Gray. Directed by David Leveaux.
  • Crew: Sets and costumes, Mike Britton; lighting, Hugh Vanstone; sound, Simon Baker; music, Corin Buckeridge; production stage manager, Julia Reid. Opened June 1, 2010. Reviewed June 2. Running time: 2 HOURS, 35 MIN.
  • Cast: Charles, Older Holly Peter Sullivan Celia Helen McCrory Mr. Brownlow Robert Glenister Ellie Eleanor Bron Young Holly Harvey Allpress/Laurence Belcher/Felix Zadek-Ewing