THE YOUNG guide said: "You are my group and I am your leader." We felt a bit like herded schoolchildren, but he was charming and blond and anyway it was exciting to find ourselves in the British Library after hours to find - what? We were on the thrilling brink of the unknown.
There were 500 of us, divided into carefully marshalled platoons, as we entered the building's calm, contemplative interior. We even included the architect, Sir Colin St. John Wilson, who had watched a rehearsal and had been so enthused at seeing his building transformed that he had returned for a second helping.
The American choreographer Stephen Koplowitz's Babel Index is a site- specific performance on a grand scale. Commissioned by Dance Umbrella, it requires a boggling orchestration of people in different places at the same time. Like Koplowitz's Grand Canyon at the Natural History Museum two years ago, Babel Index takes inspiration from the building's physical design and invokes its mission as a storehouse of human knowledge.
Outside in the forecourt, 11 draped figures stand on pedestals, like caryatids. They mould themselves in slow shapes and hold opened books, light shining from the pages: a visual pun intended to suggest medieval illuminated texts and glowing computer screens. Inside, the rest of the 54 dancers, dressed in Craig Givens's red worker-suits, are deployed on two levels, for viewing by the promenading spectators.
The opening dance, replicated on both floors, each shows 12 dancers, sitting still, then slowly expanding into action, as the taped sound of breathing is replaced by whispering voices, then Jonathan Stone's music.
We might be watching the stirring of life, the beginning of speech. And with the curves and lines of the contrapuntal bodies against a floor like parchment, writing is being created before our eyes.
The second section, a collection of separate simultaneous events, is not entirely identical on the two floors, so it is not possible for anyone to see everything. You wander around and find a sextet positioned on a flight of stairs, passing books up and down, as though knowledge is being transferred through the ages. Another group is surrounded by newsprint; a lone man lurches from side to side at the top of a vertiginous Babel tower, gathering invisible languages; and in the distance, on a high balcony, stands a line of singers.
Considered as isolated movement, the choreography is semaphoric and simplistic, but it makes an impact in its massed patterns.
This applies especially to the final section, watched by everyone from the entrance hall, as the dancers on three balconies unfurl from a spiral staircase like a scroll. They spread out and sway - a Mexican wave. Arms spike out in star shapes and brandish books the way Mao Tse Tung's crowds did, except this is a populace indoctrinated by the freedom of learning. By now the climax has arrived, with projections of script and human images. And when everything stops you have experienced something unique: a beautiful building, honoured, celebrated, and brought to unexpected life.