George Benjamin Day, Wigmore Hall, London

Ethnomusicologists are like bees, with melodies being the pollen they transfer from culture to culture. In the 1950s the great American ethnomusicologist Alan Lomax went on a song-collecting trip to Italy, and brought back recordings of a wealth of music which is now mostly extinct.

Listening to those recordings, the Italian composer Francesco Antonioni was entranced by a lullaby which he’s now made the focus for a new work, Ballata, with which musicians from the Birmingham Contemporary Music Group beat up a fine storm at the Wigmore; under George Benjamin’s direction, its intricate traceries and unexpected sonorities came across with raw intensity.

It was typical of Benjamin’s modesty that he should pack his celebratory day with other composers’ works as well as his own; another offering was the premiere of David Sawer’s Rumpelstiltskin Suite. Like Antonioni, Sawer specialises in original textures and aural transparency; I have never heard a harp sound so cavernously metallic, nor would I have imagined that a group of assorted woodwind instruments could so vividly evoke a peal of bells.

Meanwhile the bass flute which Benjamin had cast as the key instrument in his first opera Into the Little Hill was a reminder of a Baroque timbre we these days seldom hear. In the wake of the recent success of his second opera Written on Skin, this concert revival of his first – a 35-minute two-hander – has been keenly awaited. It’s a contemporary take on the myth of the Pied Piper of Hamelin with queasy echoes of current debates on conservation, immigration, and the tabloids’ obsession with child-abduction, but it doesn’t have the serene assurance of Written on Skin – you can sense Benjamin still feeling his way towards a personal operatic language.

But it possesses singular virtues, and as sung by Susanna Andersson and Hilary Summers (who was one of the singers for whom it was originally written) it packed real punch. While Andersson delivered her high-lying soprano part with ringing purity, Summers’s luxurious contralto created a foundation of velvety firmness which her physical presence – suggesting the figurehead of an 18th century man-o’-war – reinforced. Benjamin’s librettist Martin Crimp believes that an opera text should feel incomplete, and that the music should supply what is felt to be missing. Benjamin, meanwhile, has no interest in setting mundanely naturalistic dialogue. The results here may be uneven, but at moments they reached a remarkably ritual expressiveness.