While Alistair McDowall’s X furiously inspects what becomes of humanity when all one has ever known disappears at the Royal Court, Nick Payne dissects the interplay of identity and memory with considerably more calm at the Donmar Warehouse. Elegy, Payne’s 70-minute three-hander about an ageing couple’s traumatic experience with mental degeneration and the dilemmas that a revolutionary amnesia-inducing treatment creates, is short, sweet and seriously provocative. Think Eternal Sunshine Of The Spotless Mind but with less Jim Carrey and more Zöe Wanamaker.

Josie Rourke directs and Wanamaker stars as Lorna, the 60-something wife of Barbara Flynn’s Carrie (they’re lesbians, not that it is particularly important in the context of the play). We first meet them after Lorna has been discharged from hospital following an operation that has saved her sanity but that has left her with no memory of the past 20 years. As the pair’s relationship becomes clearer, the sheer sadness of Carrie’s situation is realised. The woman she has loved and been loved by, with whom she has shared a life for two decades, treats her like a stranger.

From there, Payne’s script flits backwards and forwards in time, with a series of short scenes offering snapshots of the couple’s history. There is Lorna, almost entirely lucid, reading poetry to an affectionately mocking Carrie. There is Carrie, gently bringing Lorna’s wandering, forgetful mind back to the present. These moments, weighed down with solemnity yet still brimming with life and love, are interspersed with discussions between Carrie, Lorna and Nina Sosanya’s science-babble spouting Miriam, the consultant guiding them through Lorna’s illness.

The dialogue is recognisably Payne, crammed full of half-sentences and one-word interjections, dancing lightly on the edge of naturalism. It pings back and forth between characters rapidly and engrossingly and, despite its disjointed idiosyncrasies, it is actually notably articulate – both emotionally and intellectually. Miriam is particularly well-written; her tendency to wordily prevaricate to avoid answering difficult questions directly is a neat touch, as it also introduces the more complex psychological theory underneath the play.

All three performances are gentle and understated, but there is something disengagingly clinical – perhaps exacerbated by Tom Scutt’s stark, anonymous set – in the way Payne so overtly uses his characters as vessels to present his subject matter: the dilemmas surrounding Lasting Power of Attorney, the ethics of removing memories and the very nature of the self when medicine has robbed one’s past. Elegy hypothesises the moral ramifications of such a surgical practice being made available to all, and comes down non-committedly – or refreshingly – on the fence. It is a thought-experiment at heart. A sensitive, soulful, somewhat sterile thought-experiment.

Elegy is playing at the Donmar Warehouse until 18 June. For more information and tickets, see the Donmar Warehouse website. Photo: Johan Persson