The Trama Showcase event was announced as a chance to "catch six of Brazil's most pioneering musicians" and as a "sonic timeline" from the 1960s to the present day. Organised by the Trama record label, the evening features a super-talented backing band, capable of playing every Brazilian style you can think of, while various artists troop on and off the stage, occasionally duetting or helping each other out.

Of the newer artists, Jair Oliveira is likable but Patricia Marx is particularly dreary. She's a would-be club diva with a thin voice and an uncomfortable performing style. It's left to veteran pianist Cesar Camargo Mariano to rescue the first set. Mariano plays Samambaia, a glittering, inventive solo, and Blues Walk, a cleverly worked out instrumental that makes the most of the rhythm section.

The whole shebang is being filmed by a distracting camera crew of eight, so you can't avoid the suspicion that the audience is being neglected in favour of digital video. The posh "church hall" ambience of Cadogan Hall doesn't help either, and the venue is only half full, with a fidgety crowd that starts to drift away.

Fortunately, the second set delivers much more intensity: a performance by Tropicalia legend Tom Zé and his young band, all clad in blue boiler suits. They defy the Cadogan's troublesome acoustics to pound out a manic, alternative Brazilian pop universe, with well-drilled discords and spiky unisons for mandolin and synthesizer, over which Zé rants and raves in his raggedy old voice.

You could listen to him all evening, but he stops after only four numbers with a bizarre coda in which five of the band play percussion, fading and crouching into submission, while the keyboardist menaces them with The Star Spangled Banner played on melodica. More Zé, please.