Nowadays we are addicted to true-life confessions, in which people describe their anguished responses to the deaths of those closest to them.

So there may well be fascinated audiences for Joan Didion’s The Year Of Magical Thinking. They will, though, be in for a painful surprise. For this extraordinary theatrical experience proves quite different from traditional grief-fests.

An utterly assured Vanessa Redgrave, dressed in broad trousers and white blouse, suffers an endurance test comparable with ours. Giving voice to Joan Didion’s pained memories and realisations, she occupies the empty spaces of this vast stage for 90 minutes. She rarely moves from her chair, with a succession of Bob Crowley’s bleak, sea-side backdrops falling at intervals to disclose just the same scene.

The Year Of Magical Thinking was originally an American best seller, in which Didion recorded her responses to the death of her septuagenarian husband, writer John Gregory Dunne. This extended and rewritten stage version, however, which premiered on Broadway last year, acquires a new, darker complexion, since it also faces up to the death of Didion’s 39-year-old daughter a mere 20 months later. There is no end of leaping backwards and forwards in time, possessed by the author’s recollections of temps perdu.

The Year of Magical Thinking is imbued with stinging pathos and rendered strangely dramatic thanks to Didion’s personality. She describes herself as someone who has always needed to have strict control over her life and feelings, who sets store on seeing things “straight”. Dunne’s fatal heart attack at the dinner table, while Didion is busy making a salad, precipitates a personality change. At the hospital they regard her as “a pretty cool customer.” Redgrave, speaking in low, throaty, sometimes indistinct tones, duly keeps her emotions under heavy wraps. With her husband pronounced dead and her daughter lying unconscious in another New York hospital with double pneumonia, her self-control briefly fails.

She is possessed by wild fantasy, by the magical thought that in Los Angeles, which is five hours behind New York time, her husband is not yet dead and could be restored if his body were taken there. It’s the first, recurring symptom of Didion’s retreat to the comfort-zone of magic, a belief that Dunne is not finally dead. She seems in her right, orderly mind, but keeps slipping out of it, convinced that as long as she focuses on her daughter in time present rather than time past, the woman will remain alive.

Sadly the beautiful, poetic playscript, with its dramatic paragraphing, is better appreciated on the page than in David Hare’s static, listless production. The Year of Magical Thinking, which requires an intimate studio space not the Lyttelton’s vastness, makes vivid and pathetic the struggle between Didion’s desperate fantasising and her attachment to reason and order. Yet Redgrave’s dry, monotonic, emotionally withdrawn performance does not convey any such conflict. This unpredictable but often wonderful actress rises too late to luminous, wide-eyed grief and crucially fails to embody Didion’s rapt, magical thinking.