Quaternity may very well be the British modern jazz group that you’ve never heard of or is that just me? It transpires that it maintained an active performance schedule during the 1970s, its members doubtless fitting in its gigs while juggling a variety of other assignments but was never recorded. So, this double-CD ‘previously unreleased’ collection is especially welcome.

If Lowther (at the age of 81) is now a doyen of British jazz, he was but a callow youth during Quaternity's lifespan. But here he is, his trumpet tone bright and pure, the facility quite perfect in a setting typical of its time with fusion, rock and free aspects all hinted at and absorbed.

The motifs are intriguing, the late Trevor Tomkins playing evermore complex drum patterns in the mode of the day. Fascinating to observe the presence of Green on bass, an association that continues with Lowther's present Still Waters group. Phil Lee knew his way around the templates of jazz and blues guitar, his more rock-oriented interludes fitting in well to the overall shape and direction of this music, much of it composed by him.

Each piece is cleverly structured, the underlying figures almost mesmeric in their repetition; the first four tracks are by the quartet, while the later ones benefit from the presence of Themen or Wakeman. These latter hew closer to the conventional hard bop format, although still sounding adventurous in their intentions, Lowther soloing with urgency and both saxophonists echoing the trend to tonal extremes.

The title track soon moves into the headier world of freedom, Trevor Tomkins riding out the storm as Lowther breaks cover. ‘Chinese Wand’ (by Lowther) opens with the requisite oriental touches, its repeated rhythmic sequence quite compelling, Lowther exhibiting his exquisite violin work, Lee quite spare over Tomkins’ insistent drums.

This is stirring, resourceful and finely-wrought music, with Lowther's rarely-heard violin a splendid bonus.