Theatre: A FANTASTICAL WALK

Midland Grand Hotel, London

It occurred to me, while I was wandering around it, that the Midland Grand Hotel at St Pancras would be the perfect spot for a dirty weekend, in more senses than one. The place is spectacularly filthy from top to bottom and there would be no problem about having it all to yourselves. Room service might leave something to be desired, though, since Gilbert Scott's massive Gothic edifice, a monument to the Victorian railway age, ceased to function in 1935.

Parting the cobwebs now come Deborah Warner and designer Hildegard Bechtler who, for LIFT '95 are inviting you to take A Fantastical Walk, on a route mapped out by them, through the derelict magnificence of the four-storey building. This is the team that reversed all one's expectations of a night out in the West End when they transformed the Garrick Theatre into a planked- over, dust-sheet-shrouded, candle-lit arena for the 20 minutes of Beckett's Footfalls with Fiona Shaw pacing up and down the platform built near the bow of the dress circle.

In the St Pancras Project it's the nature of theatrical experience that gets mysteriously inverted. Instead of the strong sense of group identity you're supposed to feel as an audience at a live event, you're tremendously conscious here of being on your own, since each performance is for one person only and people are admitted at a rate that rules out contact. Then again, instead of housing an event, the building is the event and Warner has been careful not to upstage it. As for that event being "live", you could say that what is magical and memorable about the experience is the fugitive way the ghosts of the hotel's past are summoned up in the non-life of its present.

A bell-boy in green uniform is glimpsed in an almost subliminal flash several flights above the stunning wrought-iron stairway. As you open a door, you startle a maid who dashes off up hundreds of steps like an unnerved animal. In one room, a pianola jerks into life with a jaunty Twenties tune, the sound echoing hollowly off peeling walls and down corridors where period shoes and used trays begin to appear outside the doors. The intonations of the past are hauntingly vestigial (a pair of white evening- gloves, say, draped over a table) and the weird temporal and physical juxtapositions (a bright yellow canary twittering in a rusty Edwardian bird-cage hung over the vertiginous stairwell or the wonderfully incongruous spectacle down in the filthy cellars of pile upon pile of pristinely white sheets) create an unforgettably comic/ poignant sense of a building suspended between lives.

Much of the time, you feel like Alice must have in Wonderland. Indeed, it's a shame the artfully conceived journey of the imagination is not feasible for children. But this must be one of the few theatre pieces where you have to sign an insurance indemnity form first and where, along the way, you encounter notices saying "Danger: rats".

n To 24 June. Booking: 0171-312 1995