An unlikely but fortunate meeting of two avant-jazz heavyweights came about in the early 1970s during an extended holiday trip to London made by trumpeter Bobby Bradford. Arranging an impromptu session with drummer John Stevens (a founding father of British free improvisation) and his group, Spontaneous Music Ensemble, Bradford appeared on two classic volumes for the Nessa label. The two complementary sets are reissued here under the slightly confusing title (given the name of the Stevens-led group) Spontaneous Music Ensemble. Bradford here is in excellent company and sounds more forceful than on his typically reserved contributions for clarinetist John Carter…