Critical Mass, Almeida Theatre, London

Critical Mass, devised by Emma Bernard and Orlando Gough, deserves a long life. As the final offering of Almeida Opera 2007 (a mixed bag of contemporary music and opera), Critical Mass is hugely compelling. Devised by Streetwise Opera and featuring members of The Shout, this is a work for the community by the community.

Streetwise Opera was set up five years ago in response to an MP's remark on the homeless – the people you step over when you come out of the opera. Streetwise comprises people – all sizes, ages and ethnicities – who have experienced homelessness. Critical Mass (the title is wilfully ambiguous) is the result of workshops held in four London centres for the homeless.

Much of the material was provided by the participants. The action concerns an imagined conference of global delegates discussing global issues, satirising the vacuous, clichéd, gobbledy-gook management-speak favoured by many of today's politicians. The cast of 40, besuited, with briefcases, sit in rows, jumping up and down to deliver meaningless declarations, all wildly applauded. Orwell's Animal Farm comes to mind.

From time to time a song breaks out – Hebrew, Estonian, Gaelic, gospel – quickly overwhelming, engaging, subverting the delegates; music, not words, leads to cohesion. Tea arrives on a trolley, an elderly black lady pouring; four "suffragettes" with "Votes for Women" sashes pass by.

There are no "characters", only individuals in a crowd of massed singers, skilfully directed in their movement by Bernard. There is no orchestra or conductor; all songs and choruses are unaccompanied. Melanie Pappenheim leads the last song in German: "Everything is transitory. Life lasts only for a moment."

Numerous attempts have been made to present "new" opera – but is this opera? Well, not in the sense of grand singers, choruses, orchestra and staging, but in a much more real sense – the political sense of Mozart, Beethoven and Verdi – it is. Gough and Bernard have confronted contemporary life, wittily but poignantly. Critical Mass – relevant, intelligent, touching, powerful – should be widely seen. A tremendous achievement.

Interesting? Click here to explore further