Perhaps one of the few working musicians with a PhD in theoretical physics, saxophonist John Butcher has been an important contributor to the free jazz genre since the late 1970s. In the mid-'80s, Butcher and pianist Chris Burn developed the London Improvising Ensemble, which later evolved into the Chris Burn Ensemble. Butcher also played and sometimes recorded with Derek Bailey and bass player Matthew Sperry, among others. Since the late '80s Butcher has worked frequently in a trio with guitarist John Russell and violinist Phil Durrant, who both played with him in Burn’s Ensemble, and since the '90s he has collaborated with the electroacoustic improv group Polwechsel.