Promoters sometimes have their doubts about free-improvisors, so Evan Parker's trio was lucky to be playing two festivals in one on Wednesday. Parker, the British saxophone virtuoso whose multi-melodic 20-minute soprano solos defy the laws of human respiration, was simultaneously gracing both Scott Walker's Meltdown and Leo Records' Unsung Music Festival.

He was at London's Purcell Room with the furiously energetic bassist John Edwards and the guitarist John Russell, a restrained descendant of the Derek Bailey school of swinging atonalism. The three played in various permutations, but Edwards was a dynamic presence throughout, goading his partners with explosive pizzicato sounds or tom-tom thundering on the body of the instrument, placating them with abrupt shifts to softly bowed chords.

There are no orthodox melodies - the band's variety comes from its sense of drama, alertness to dynamic changes, and explorations of a variety of free-harmony possibilities: surging, low-register bass figures against Parker's alternately plush and venomous tenor; pealing bell effects with the soprano against tinkling guitar chords; flat-out collective jams that resemble a kind of arrhythmic swing.

The band played with a fierce, unswerving energy, which was needed, as it had two tough acts to follow. The Russian duo of accordionist Evelin Petrova and trumpeter Vyacheslav Guyvoronsky had overlaid folksy accordion patterns, oompah rhythms and dark, didgeridoo-like sounds with contrasting talkative, inquisitorial vocals, sometimes winding up in laughter or mock-tears, while Guyvoronsky wound wraith-like trumpet lines around her.

They brought the house down, but the pianist John Wolf Brennan wasn't far behind with a remarkable set that mingled John Cage abstractions and free-jazzy chordal exchanges with his percussionist Christian Wolfarth.