THEATRE / The first casualty of war: Paul Taylor reviews The Big Picnic in Glasgow

Bill Bryden's The Big Picnic is a moving experience in more ways than one. A technically audacious First World War spectacular, it's performed in the vast abandoned engine shed of the Harland and Wolff shipyard in Govan, Glasgow. Here, in the apposite atmosphere of a bleak industrial machine, the audience literally follows the young Pals Brigade of Govan volunteers to Flanders and through the inhumanities of trench warfare to their massacre in 1917. You go on the journey either as a promenader or as a sedentary passenger on the mobile seating that slides back and forth down the 250ft nave of scaffolding within which the designer, William Dudley, has recreated the muddy, smoky wasteland of the Front.

At first, there's a perfect match between the kinaesthetic thrills imparted by the show's technology and the nave elation of these youths eager to prove their manhood. It's a truly uplifting moment, when, to the resonant bagpipe thrum of John Tams's music, the huge doors at the end of the first acting area part and, with the seated audience sliding alongside them, the kilted brigade march straight through to the trenches. It's both psychologically expressive and magical, like some malign Narnia-effect, this telescoping of time that so quickly propels the men from the warmly familiar to an alien, lunar landscape.

As the war proceeds, though, you may worry that the show's anti-Brechtian efforts to include you in the experience merely highlight the privileged luxury of your position. Following the action, the promenaders could be a crowd at a golf tournament and as for those of us in the seated area, let's just say that we saw passive service at the Front. Technically, the show is a marvel. Who could forget the moment when the red- maned Angel of Mons, the Fate figure who twirls suspended from the gantry, sweeps forward to pick up one of the slain warriors in an aerial pieta. And who could be quite sure that this, or the son et lumiere of the battles, or some of the more Seventies- sounding folk-rock, was at a respectful enough distance from the aesthetic of a big- budget musical? The sincerity of this pounds 1m venture is palpable; the taste questionable. At times, this excursion to the heart of darkness is in danger of reducing Flanders fields to a high-minded theme park.

Bryden's scenario, acted with gritty commitment, works best when an empathetic non-naturalism brings home some significant truth, as when the growing psychological distance between the soldiers and their girls back in Govan is paradoxically illustrated by juxtaposing them in couples on the battlefield reading out their strained letters. Or, at the stirring conclusion, when the men seem to rise from the dead, march back to Govan and pose as the statuary in their own war memorial. They look too salubrious, though, as do the conditions and the carnage throughout this flawed but unforgettable piece.

To 30 Oct (info: 041-226 4826; booking: 041-242 3666)