Jazz Line-Up this week focuses on "Big Jazz". Kevin Le Gendre discusses with bandleaders Tommy Smith and Guy Barker how to score and arrange for large ensembles. Kevin illustrates the composition of Smith and Barker and how they have applied an orchestral discipline to works that include and require improvisation. Both composers have, and do, release large scale works. Barker for the annual 'Celebration of Song' at the London Jazz Festival, requiring multi-vocalists and concert orchestra with combined Big Band and Smith with his re-arrangement and extension of the Gershwin's 'Rhapsody in Blue'.