A Nitro At The Opera, Linbury Studio Theatre, Royal Opera House, London

Sunday's link-up between the black theatre company Nitro and the Royal Opera's development arm, ROH2, was the glamorous tip of an improbable iceberg. For a year, the organisations have worked with nine black composers to counter what most people see as the inbuilt racism of the opera world - even if they don't call it that. That the showcase delivered high-quality results should surprise nobody: the works come from well-established musicians who somehow hadn't got through the door before.

What apparently was a surprise was that the free afternoon event became a hit. The Floral Hall area swarmed with a lively, mixed and inquisitive crowd, and there were long queues of people who couldn't get into the main performances. After taking such trouble with the preparation of the event, the Royal Opera could have given it more than token exposure: a full weekend or another Sunday at the least, and they could have got away with selling some of the tickets, too.

But that frustration failed to dampen a spirited sequence that featured Curtis Walker as MC and public workshops on Scott Joplin's pioneering opera Treemonisha. At the centre were a triple bill of mini-operas and a recital of new arias. The three staged pieces made savvy but contrasting use of their 20 minutes. Clement Ishmael went for gritty realism in Grazyna: The Triumph of the Queen. For this gruesome Polish folk tale of a consort prepared to die by deception rather than endure the king's warmongering, he devised a lean, polished and tightly knit score that could still expand to give the central encounter and the stark finale the space they needed.

Bird of Night by Dominique Le Gendre used a Caribbean story with a magical African dimension - dreams of freedom become powers of flight - to which she responded with a light touch and a generous imagination. It is like a Ben Okri novel translated into music, as the spirit world and the mundane world, the comic and the tragic, mingled towards a shocking and deflating end: the one point at which this beautifully concise score could have done with an extra half-minute.

In Another America: Earth, Errollyn Wallen took a multilayered view of a single cruel event, the dispossession of a poor couple, surrounding it with other human responses to the unbearable, from religious fundamentalism to visionary science. Intense vocal lines pushed against the limits of the voices and piled into dense, complex ensembles with a deep-toned accompaniment, apparently resisting the opportunities for light and shade to make the most of a sudden climactic silence.

A strong cast directed by Bill Bankes-Jones shared all three operas, with Jacqueline Miura, Angela Caesar, Patricia Rosario and Omar Ebrahim shining especially.

In the Crush Room, five songs with piano showcased more composers. The more dared, the more gained, was the message, as Dainty Drysdale seared her way with an astonishing variety of expression in such a short time through a scenario of domestic murder inspired by an Eminem rap. Ola Onabule dared, and brought off, a shock Puccinian flowering of melody as the ecstasy of struggle took over. Alex Wilson managed something similar the other way round, as pounding pulses broke up a deathly narrative. Nicky Brown came up with a suave art song, and Tunde Jegede, a simple duet that sounded like part of a larger whole.

Ailish Tynan, Hubert Francis and Adrian Kelly performed with aplomb, though the jazz demands of Orphy Robinson's offering defeated the available resources - it's now supposed to be up for future workshopping. That would be something, because the big question after a stirring day has to be: great stuff, but will that be all?