Originally an intimate meditation prompted by Poussin's famous sequence of paintings depicting baptism, coming of age, marriage, penance and so on, Seven Sacraments, an Artangel project premiered at the Brighton Festival last week, has burgeoned into something very grand. It is now a dramatic oratorio, complete with orchestra, soloists, vast choir, and even dancers. Yet the message it conveys is not the rock-solid affirmative of Handel and co. It's the unsteady questioning of Mr Ordinary, who is none too sure whether and what he believes in these days but who, undergoing some undefined mid-life crisis, has discovered a nostalgic respect for the old forms.
When this Neil Bartlett narrator-figure first appeared at Wednesday's premiere, ambling up the aisle of St Bartholomew's, muttering, I probably wasn't alone in thinking him a stray nutter who had blundered into our concert. It was registering the radio-mike that made you sit up. Like most of us, this man hasn't been to church in ages. But he remembers all the words, well ... some of them. "Without some ceremonies it is not possible to keep any order," he quotes from the preface to the Book of Common Prayer. For 400 years, he reflects, people assembled to recite the same words on all the occasions that mark out the journey from birth to death. But what about us, now? When even the font of St Bart's has to be labelled for the benefit of clueless visitors, what words can we use ... to welcome a child, to join hands with our partner, to say farewell?
An answer, of sorts, swells beneath his voice in the form of Nicolas Bloomfield's musical score, which sets a variety of religious texts: scraps of Donne, some psalms. Ironically the choral words, in this barn-like venue at least, are mostly lost to the swimmy acoustic. But the ruminative, misty, strings-and-brass "Jerusalem" sound - so very English - is emotive in itself. Six more "visitors" arrive on the dais, who turn out to be dancers, then swarms of schoolchildren, about 60 of them. And it's the contribution of this chirruping, fidgety mob throughout the piece that saves it from becoming over-earnest, hectoring or heavy.
Contemplating growing up, Bartlett poses as a priest taking his charges through the questions they must answer before first communion. "Do you promise to respect all people?" "Yes!", shouts a boy, "'cos they might give you a present!." "What advice would you give to other young people?" "Don't pick your nose or your head will cave in," suggests another. The children devised their own responses. No author could have invented anything so realistically anarchic, from some, or so cravenly goody-goody from others. And this element will gain different emphases as Seven Sacraments changes its junior cast for Nottinghamshire and London.
Using dance in a religious context could smack of the happy clappies, but under Leah Hausman's direction the movement was spare and beautifully executed, and added yet another element of stylistic surprise to relieve the dogged ticking-off of seven ceremonies. It was moving, too: in the protective mime of the "godparents", arms encircling a child; in a flagrantly sexualised solo for Wendy Houston's Mary Magdalene, washing Christ's feet to illuminate the sacrament of penance.
We never get to know what prompted the narrator's black night of the soul. But Bartlett's anxious, angular, confused and questing character speaks directly to us all, including those who believe themselves beyond agnosticism. When someone close to us dies, he points out, most people's response is: "I don't know what to say." For hundreds of years, the script has been written for them.
Nottingham Southwell Minister (0115 941 9419), 22 & 23 May; Southwark Cathedral, SE1 (0171 741 2311), 28-30 May.