Edward Rushton's chamber work opens its UK tour after being premiered in Zurich in March, directed for The Opera Group by its former artistic director, John Fulljames. Born in Norwich but now based in Switzerland, Rushton is an experienced opera composer. His new piece, scored for just five principals and five instrumentalists – here the excellent Ensemble für Neue Musik Zürich, led by conductor Tim Murray – is technically secure in all departments; it's particularly gratifying to hear vocal lines that so consistently work with, as opposed to against, the human voice.

The drama itself is more debatable. Indian poet Jeet Thayil's libretto boldly presents a scenario about a group of four London-based Islamist terrorists, two of whom eventually succeed in their aim of becoming suicide bombers.

Amid this challenging material, though, comes the intervention of a ghost. Adding huge splashes of colour to the piece, yet also enormous dollops of whimsy, are the appearances of baritone Omar Ebrahim as Babur, the first of the Mughal emperors (1483-1530), known during his lifetime for his writing as well as his military ruthlessness. In his posthumous visitations, however, Babur seems more of a drunk and a pothead, whose carefree philosophy does not persuade the young jihadists – brilliantly drawn by Kishani Jayasinghe, Annie Gill, Amar Muchhala and Damian Thantrey – to desist from their murderous enterprise. The result is weirdly unconvincing, not helped by Rushton's score, which is cleverly written but largely unmemorable.