Sebastian Faulks’ wonderful 1993 novel Birdsong is a love story, a chronicle of horrendous conditions in the trenches of the First World War, and a tale of amazing human courage and resilience.

It’s a novel to wallow in, but Trevor Nunn and the writer of this stage version, Rachel Wagstaff, have brilliantly distilled a three-hour play without losing the density of the subject matter or the poetry of the story.

Stephen Wrayford, perfectly embodied by Ben Barnes – tall, dark, impulsive and stubborn – goes to Amiens in 1910 as a 20-year-old textile apprentice manager, embarks on a torrid affair with his host’s wife, Isabelle (Genevieve O'Reilly), and finds his rustic idyll literally engulfed by the First World War.

He becomes a lieutenant in the army, drawn to the dangers and horrors of the tunnel diggers, or sewer rats as they were called, having lost Isabelle who, finding herself pregnant by him, has run away in shame. The Battle of the Somme takes Stephen to the edge of the abyss, and a dark fortnight or more of the soul.

It is unimaginable what these soldiers endured, but Faulks has given us a good idea. Nunn and his ingenious designer, John Napier, have conjured a superb, fast-moving show of projections, terrifying sonic effects and, especially, full-on camaraderie, in scenes of letter-writing home, sing-songs round the piano, and almost shocking self-sacrifice and fortitude.

Using scrims, clever scene changes, music hall patter, and a fully mobile cast of 15, the play shows how the fishing waters round the Somme, and the rustic beauty of this area, are transformed into the sort of killing fields that survivors vowed would never be seen again.

Barnes, like Wraysford himself, leads from the front, ably supported by Nicholas Farrell as both the cuckolded husband and a Scottish general, luminous Zoe Waites as Isabelle’s sister, bearing a message of hope, and, especially, the outstanding Lee Ross as the charismatic tunneler Jack Firebrace, devoted to his ill son back home, and Stephen’s unlikely companion in the hour of darkest need.

I’m sure, one day, the book will become a great film; for the moment, it is undoubtedly a great theatrical triumph.