R C Sherriff's eyewitness account of life and death in the trenches is straight from his own experience on the frontline and it still packs the emotional punch that made it a phenomenon after its 1928 premiere, especially in this centenary year of the Great War.

Paul Hart's production unfolds on Katie Lias' evocative two-tier set, with sandbags on the ‘top' and an atmospherically lit (David Holmes) dugout below. It focuses almost unbearably tightly on the intense relationships of men of different ranks living close together under fire.

Sherriff gives an unflinchingly forensic though compassionate account of how differently men react to being so close to death and Hart's first-rate cast calibrate the different emotions each man feels over four days in this hellish situation. Whatever else they feel, most are preoccupied with the basics of food for comfort and drink for courage - and to numb mental anguish.

Captain Stanhope presides over this little company, an exemplary officer adored by his men, who has seen and endured too much for whiskey to keep him sane. The arrival of his girlfriend's idealistic young brother Raleigh, who has manoeuvred to serve under him, threatens to tip him over the edge. And orders from above to organise a suicidal raid, on which he's forced to send young Raleigh and his best friend and mentor ‘Uncle' Osbourne, are the last straw.

William Postlethwaite is mesmerising as Stanhope, a believable all-too-young public school hero, whose men would follow him anywhere, genuinely compassionate, but dangerous and mercurial, damaged by what he's seen and endured, and his bitter realisation of war's futility His relationship with Jim Creighton's brave, warm, humane Osbourne is extraordinarily touching and his response to Raleigh's presence, from brutal to nurturing, is beautifully nuanced. James Mack is perfect as Raleigh, with the ‘shining morning face' of the idealistic schoolboy, bravely hiding both fear and dawning disillusionment. Watching him with Creighton's Osbourne before the raid you get the feeling that time has slowed as they talk about the New Forest and quote Alice in Wonderland.

Edward Killingback is perfect as all-too-human Hibbert, whose stand-off with Stanhope over his understandable reluctance to fight provides a moment of terrifying tension. Robert Fitch is equally effective as the Colonel, the prototype of out-of-touch commanding officers (think Blackadder). Jonathan Dryden Taylor makes a ‘valiant trencherman' enjoying available rations as best he can. Together with Ben Worth's sparky, cheerful Mason, the company cook and a down-to-earth enlisted man to whom the largely schoolgirl matinee audience especially warmed, he provides some light relief in a production that vividly evokes and explores the horror, pity and futility of war.

The schoolgirls were visibly moved. How lucky they are to add this experience to their First World War studies.

Journey's End continues at the Watermill until 11 October