THIS has been a heavyweight, even harrowing start to the autumn season at York Theatre Royal, where on e study of man's inhumanity towards his fellow man, George Orwell's 1984, has been following by another this week.

If Headlong's 1984 presented an exploration of surveillance and identity wrapped in the Orwellian vision of the future, then Nicholas Wright's stage adaptation of Pat Barker's novel Regeneration is a study of the past that is uppermost in our minds this year: the centenary of The Great War. Both plays are refracted through the present and the lessons learned or, invariably, not learned from Barker and Orwell's depiction of our patterns of behaviour. What links the two is the focus on the impact on the individual, be it Orwell's rebel diarist Winston Smith or the two war poets, Siegfried Sassoon and Wilfred Owen, in Regeneration.

Directed by Simon Godwin, this Touring Consortium Theatre Company and Royal & Derngate, Northumberland co-production is on tour before the world premiere transfers to the West End. It is theatre of the highest quality, so astutely and movingly written by Wright.

Regeneration is a "war saga in which not a shot is fired but where battles are fought for the minds of men". Those battles are being fought inside the mind as a result of the damage inflicted in warfare, in the trenches, on the front. Wright's production begins in 1917 as Tim Delap's Sassoon makes his public declaration against the war, "an act of wilful defiance of military authority". Sassoon faces the audience; the figures of authority sit as a bank of four, seen from behind. It is a powerful opening image by director Godwin, whose production is visually memorable throughout.

The play then centres on Craiglockhart Hospital, where Stephen Boxer's Captain Rivers is in charge of the rehabilitation of shell-shocked patients, among them the public school-educated Sassoon, with his "nervous breakdown" and hallucinations; grammar school-educated Owen (Garmon Rhys); and working-class Bradford officer Billy Prior (Jack Monaghan), who arrives mute but ultimately has as much to say as Sassoon.

Billy's story is often to the fore, crucially giving the play its social cross-section, while Rivers's methods, so at odds with the electro-shock treatment elsewhere, go to the heart of two dilemmas. Namely, patching up a man to send him back to the front and dealing with men who are torn between their conscience and sense of duty to their fellow man.

Sassoon is driven by his conscience; Owen, for all the sentiments of Anthem For Doomed Youth, answers to the call of duty; Prior wonders where he fits in at all. All this is intelligently presented by Wright's script, Godwin's direction and the performances of a uniformly superb cast. Alex Eales's set designs, austere for Craiglockhart, beautifully bleak for the Chelsea Physic Garden, play a significant part too, while the discordant sound designs of George Dennis, music of Stuart Earl and illusions of Richard Pinner all contribute to the representation of mental disorientation and shell shock.

This is a five-star production of a five-star story.

Regeneration, York Theatre Royal, 7.30m tonight; 2.30pm, 7.30pm tomorrow. Box office: 01904 623568 or at yorktheatreroyal.co.uk