The Veil Of The Temple, Temple Church, London

This is John Tavener's magnum opus. At seven hours' duration, lasting from dusk to dawn, The Veil of the Temple is one of the longest continuous choral pieces ever written. Around 150 performers take part in a score requiring duduk, Tibetan horn, simantron and Indian harmonium, as well as soprano soloist, choir and organ, a supply of candles and copious amounts of incense. Embracing diverse religions from Islam to Christianity to Hinduism, this is a universal hymn to God. Neither a concert work nor strictly liturgical, it takes the form of a prayer anticipating the coming of Christ and was inspired by Orthodox church vigils.

The beautiful 800-year-old Temple Church provided an ideal setting for this monumental creation. Its fusion of Gothic grandeur with the richness of Jerusalem complemented Tavener's own musical bringing together of East and West. The building was used to splendid spatial, visual and acoustical effect, with choirs clustered around the chancel and chanting singers processing up and down the aisles.

Outside, the soprano Patricia Rozario launched the piece with words by the Sufi mystic Jalaluddin Rumi. The work progressed through its eight varied but thematically related cycles with the inevitability and building intensity of Byzantine ritual. The breaking of dawn coincided with the melismatic, ecstatic seventh cycle, while the final section provided an overwhelming climax of culmination and renewal. The chorale-like Upanishad Hymn, underpinned by Hindu chanting, filled the church with a colossal, almost tangible mass of sound, the entire range of voices at full stretch augmented by five brass players and timpani.

At the end, the participants processed out of the Temple Church, still singing, followed by the composer, who led the audience drifting into the daylight like the ghosts of the Knights Templar invoked in the final cycle. Appropriately, the work did not conclude conventionally, but gradually receded out of earshot, continuing to resonate in the mind long afterwards.

The Veil of the Temple elicited superhuman contributions from the performers. The singers maintained an extraordinary level of intensity throughout the performance. The conductor Stephen Layton has been involved closely with the work's three-year evolution, a collaboration that yielded an unfalteringly intuitive understanding of the musical, architectural, spiritual and logistical implications of the score.

John Tavener has brought into being a uniquely significant choral work of immense cumulative power: a glorious, transcendent achievement. As the crowds began to disperse, many people were heard thanking the composer for his work - acts of spontaneous gratitude budding from Tavener's own large-scale offering to the Deity. The 12 Anthems to be selected from the cycles of The Veil of the Temple should go some way to capturing its spiritual essence.

A second all-night performance takes place in the Temple Church, relayed to screens in the gardens on Friday