The Notebook (Battersea Arts Centre)

It's easy not to think about what those poppies on our lapels stand for. We've put a coin in the bucket and our duty is done; no further reflection required. But then a piece of theatre like The Notebook comes along and forces the brain to engage – there is terrible human suffering behind those little paper petals.

The genius of this two-hander, Forced Entertainment's adaptation of the book by the Hungarian writer Ágota Kristóf, is its indirect approach to the topic. A pair of unnamed twin brothers, played by Robin Arthur and Richard Lowdon, are evacuated from the 'Big Town' to their grandmother's house in the countryside, but for the first half of the performance, the wartime context is more or less irrelevant.

The boys' story, which they read from the eponymous notebook in which they have written a series of accounts of their lives, is initially concerned with the cruelty imposed on them by their grandmother, the grim sexual exploits (and exploitations) of their neighbours, and their attempts to harden themselves up to this new rural life. It's only later, when the brutal realities of wartime begin to directly impact on the twins' lives, that we can look back and read their earlier misadventures as symbolic of the horror to come, not just in their world, but of war more generally.

Arthur and Lowdon's emotionless delivery, like the story itself, is unnerving. The men move and speak together, their synchronicity barely faltering and their commitment to these strange little everymen unfailing for the entirety of the two-and-a-half hour performance. It's an admirable feat of storytelling whatever your feelings are about the story being told.

The language is deliberately exacting: the boys explain early on how they've strived for "precision and objectivity", for "faithful descriptions of the facts" in their written accounts. Director Tim Etchells' decision to have Arthur and Lowdon read from their notebooks throughout brings this precision to the act of performance itself. The Notebook is fiction, not documentary, but Forced Entertainment's telling bears a certain resemblance to the headphone-wearing verbatim technique of Alecky Blythe.

As a result of this focus, the narrative is at once highly evocative and distancing, the audience left to construct their own responses to the scenarios the boys describe, projecting our confusion and revulsion onto them and the other characters in their tale.

The production is as stripped back as the story itself. Jim Harrison's barely changing lighting design leaves Arthur and Lowdon nowhere to hide, while the design (by Lowdon), offers no concessions to theatricality – the two chairs the performers move about the space with them are utilitarian and the men's costumes are history-teacher chic. The Notebook may technically be set in Eastern Europe during and after the second world war, but the moral struggles contained with it are universal.

It's not an easy show to watch. Two and a half hours is a long time to sit in one place, and there are plenty of moments where you wish you were somewhere else. By The Notebook's shocking, powerful end, however, you understand that it had to be that way – they're called uncomfortable truths for a reason.

Running time: 150 minutes, no interval

The Notebook runs at the Battersea Arts Centre until 14 November.