Pascha Nostrum, Catholic Chaplaincy, Oxford

An academic lays his head on the composer's block

James I of England would not have approved. The Stuart monarch, in 1605, forebade the public staging of biblical drama. Nowadays we have fewer scruples. Hence admired stagings by Jonathan Miller and Deborah Warner of the St Matthew and St John Passions; Tom Hawkes's presentation of Handel's Brockes Passion; Birtwistle's Glyndebourne Last Supper; and now, the culmination of John Caldwell's Easter trilogy (Good Friday and The Word) with Pascha Nostrum.

As its venues (Oxford's Catholic Chaplaincy and Tewkesbury Abbey) confirm, Pascha Nostrum is not so much an opera as a church parable. The opening plainsong ("Crux fidelis") breathes the same atmosphere as Britten's The Prodigal Son or Maxwell Davies's The Martyrdom of St Magnus. The narrative exchanges are as simply stylised as The Burning Fiery Furnace. At no time does director Nick Kelley venture beyond the plain and direct.

If the result is a lack of any memorable symbolism to penetrate and interpret Caldwell's evocative, questing score, it serves one useful purpose. The white-clad Christ (William Tallon) becomes the central symbol. Like William Dazeley's Christ in the Birtwistle, Tallon glides in and out of the action to deliver a homily here, a pep-talk there. The scene where he upbraids Cleopas (searingly delivered by Edwin Hawkes) on the road to Emmaus is one of the most galvanising; so, too, the late rebuttal of the disbelieving Thomas (James Brown).

Caldwell's writing has acquired a greater cogency and restraint since the earlier operas. Its modernism is less gestural, the Romantic outbursts better dramatically aligned. That an Oxford academic, steeped in medieval music history, is putting his head on the block as a composer deserves respect. So does the commitment of his young cast, strong neither vocally nor dramatically, but clearly involved.

Benedict Linton's Evangelist is probably the strongest deliverer, though ill-placed rearstage in the cavernous Chaplaincy chapel. The weakest sequence is the Old Testament narrative, where Moses (Christopher Eastwood) wades through a wearisome arioso exposition, partly inaudible due to overweighting in the orchestra and a slight overscoring.

Elsewhere, conductor Ben Nicholas got much right: the strings of Warwick Cole's Corelli Ensemble were good, despite an over-shy violin solo. Caldwell's score, despite the odd museum curio of chromatic modulation, is never better than when employing clarinet in dark, low register, illustrating with exquisite touches for flute or oboe with clarinet in paired thirds that eerily shift in and out of focus, or punctuating with sly slivers of percussion, horn, trumpet, trombone.