Half a century after the label third stream was first attached to an area of music where jazz and classical currents could mingle, these can hardly be deemed uncharted waters.

And perhaps less treacherous as a result.

The strength of Blue Latitudes, a ten-part, hour-long work commissioned by Birmingham Contemporary Music Group and Birmingham Jazz from New York trumpeter Dave Douglas, lies in its composer's hindsight as much as in his mature even-handedness.

Taking his inspiration from an account of Captain Cook's voyages of discovery, Douglas uses the analogy of the meeting between an oral tradition - himself, bassist Mark Dresser and drummer Susie Ibarra - and a written one - the musicians of BCMG.

The ten-movement work has vivid programmatic elements: doldrums and mundane frustrations in Life At Sea, sliding and scraping natural forces in Sailing On Ice, woozy carousing and its flatulent postscript in Drinking Song Discovery.

It also has purely musical delights: the physical pulse and joy of improvisational surprise we would expect from a jazz composer set against Douglas's obvious desire to exploit the wider textural range and precision ensemble work offered by BCMG.

All three jazz soloists shine, and the whole is further energised by conductor Peter Rundel.

The influences upon Douglas are illuminated in two classical works he has chosen for the second half - concerti from Webern and Ligeti - and the long and rewarding evening ends with three free improvisations from the jazz trio.

Neither Douglas nor BCMG will remain in this musical space (Endeavour is too confining in the long term), but it has proved a remarkable voyage of discovery from which both sets of players - and their audience, too - are likely to go forward changed for the better in some subtle way.

* Now touring, including Shrewsbury on Thursday.

Peter Bacon