Call him Payne the Brain. Not in the sense that Nick Payne is a raving genius (nor to deny it, ahem), but rather in the Welsh sense, like “Jones the milk” or “Evans the bread”. Payne has carved a niche for himself in dramatic examinations of that knot where mind, brain and identity meet and tangle. His 2012 breakthrough Constellations relies more on multiple quantum universes, but we see a lover’s behaviour change due to a brain tumour; in 2014, Incognito included a pencil portrait of the historical “Patient HM”, whose brain surgery for epilepsy left him with chronic amnesia – every time he met his psychologist was, for him, the first time. Now Elegy revisits the same territory in greater detail and depth.

Lorna has a degenerative disease which will kill her if part of her brain is not removed; this world has the technology to replace the “wetware” with a silicon chip which will carry out the same brain functions. What cannot be replaced are the memories contained therein, and in this case they are the memories of Lorna’s loving years with her wife Carrie. Payne uses reverse chronology: we begin with a meeting between Carrie and a distant, post-op Lorna, and work backwards through the severe stages of brain malfunction to the initial consultation about this procedure. As in Harold Pinter’s Betrayal, we come to grasp what has been lost by seeing it restored scene by scene, and grow conscious of the extent of Carrie’s loss, the more so in that it is grief without death, without even physical absence. Barbara Flynn is affecting as Carrie, but it is Zoë Wanamaker who has to pick her way backwards, as it were, along the path of Lorna’s suffering and... cure?

Tom Scutt’s set for Josie Rourke’s fine, unshowy production is dominated by a cloven tree trunk in a glass case. The symbolism isn’t hard to decode, especially when the case fills with a dry-ice fog during scenes of Lorna’s affliction. The third character, Nina Sosanya as neurosurgeon Miriam, is given a verbal tic, namely frequent interjections of “You know what?” That’s the question at the core of it all: even as regards ourselves, we know... what, exactly?

Written for the Financial Times.