"Follow the dancers," intoned the Woman in White to the group assembled outside the British Library. "I'm leaving now." And she scarpered. The two Women in Yellow, who had been scuttling and scuffling on the ground in crab-like combat, suddenly leapt up and sprinted in the opposite direction.
Our motley group of 30 hesitated momentarily, then headed after them, a ragged line of dance- goers variously running, trotting and walking. Some kids leaned over their council-block balcony and scoffed "Argentina!" at our shambling group. The rest of the country may have been celebrating England's football victory, but we were on an hour-long guided tour like no other. This was city:skinned, a promenade performance through the hinterland of King's Cross conceived by Carolyn Deby, whose group Sirens Crossing specialise in site-specific events. A strange sight we must have been, chasing the Women in Yellow as they hopped and skipped ahead of us like fireflies at dusk.
As night fell, we walked through a post-industrial wasteland to a derelict warehouse. Inside, a woman flung herself against the wall, querulously asking, "Who's there?" as muffled speech filtered from the next room and footsteps creaked eerily across the ceiling. There were ghosts of the past, too, in another disused building, the dancers arrayed down a corridor, swivelling on the spot to the distant hoot and grind of trains leaving King's Cross station.
We trailed along a darkened canal towpath, barges lowering in the scummy water, through to the graveyard of St Pancras Church. Amid the shadowy trees, spookily aware of the dead beneath us, we watched the five dancers silhouetted like wraiths against the neon glow of the distant road, before emerging, transfigured, into the relative normalcy of St Pancras Road.
More a lived experience than a watched performance, city:skinned is based on themes from local history. During the building of the 19th-century railway, for example, corpses in St Pancras were disinterred and moved uphill, in an operation (overseen by none other than Thomas Hardy) that left more gravestones remaining than bodies.
You don't need to know this, for the mystery tour works its magic through evoking the submerged memories and forgotten layers of history that haunt the modern city. What you do need, though, are sensible shoes, and an umbrella, just in case.
· Until June 29. Box office: 020-7387 0031.