BBC Concert Orchestra, Nu Civilisation Orchestra, Lockhart, Queen Elizabeth Hall

Any conductor who ends a concert with only one leg on the ground, as if engaged in the Highland fling, is either a little fanciful or has been utterly carried away. In Keith Lockhart’s case last night, it was probably a bit of both. No-one can take charge of Duke Ellington’s big band tone poem Harlem by impersonating a lamp-post, especially at its roaring end, the epitome of jubilation in sound.

But the BBC Concert Orchestra’s transatlantic Principal Conductor is also a conscious showman. Sometimes his hands trace such sensuous curves that you feel he’s stroking a Ming vase.

All his gifts for gusto and delicate display were needed by the climactic event in the Rest is Noise festival’s American weekend. A listener learning their early 20^th century music history from this series would get a fashionably lopsided view of the significant terrain. No Sousa marches, no Victor Herbert operettas, barely a peep from musicals and the Great American Songbook; only the "radical innovators", please, and then with an African-American emphasis. But this concert, labelled Hidden Voices: Emergence of the American Sound (hidden? Duke Ellington?), eventually got the blood racing, and exhumed a few useful curios along the way.

What joy to hear the screams, slitherings and wah-wah trombones of 'The Mooch'

Slow to start, though, oh boy. First, the Rest is Noise lecture to the audience, less irritating than usual. Then came Henry F Gilbert’s The Dance in Place Congo of 1908, timid WASP exotica from a New Englander who pioneered the use of American folk material in classical dress. Now I know why the piece’s 1977 recording used an extensively cut score: heard complete it’s a long drag, with the bright Creole dance tune almost crushed under clumsy symphonic sticking-tape and ponderously picturesque elegies for the noble slaves. Some of the work’s naïve charm came through; not for 20 minutes, though.

On then to another resurrection and the 1930 Afro-American Symphony of William Grant Still, the first African-American composer to break into the country’s musical establishment with music performed by major orchestras. You wouldn’t guess from its neo-romantic musings that Still had been taught by Edgard Varèse, whose modernisms he absorbed only to spit out. Lockhart’s Ming vase hands were kept very busy here, shaping the 12-note blues themes, garlanding the woodwinds’ sighs, or keeping the music’s cakewalk strutting, banjo and all. Pleasant enough in a watery way; but where was the punch, where was the fire? Where, especially, were the memorable melodies? Apparently Still was sniffy about Gershwin and felt he’d pinched one of his riffs, but Gershwin the white man had the searing tunes. I kept thinking of Porgy and Bess.

As soon as the concert's second half got underway, another big missing ingredient arrived: jazz. The Nu Civilisation Orchestra spread their hot wares over stage, first with an Ellington medley arranged by the band’s director, Peter Edwards. What joy to hear Ellington’s distinctive harmonies and instrumental colourings in the Cotton Club screams, slitherings, and wah-wah trombones of The Mooch (the Duke, pictured right). The right stuff at last! So right, indeed, that I didn’t want the music’s structure imperilled by bursts of improvisation. But these were jazz musicians; the improvisations came. Some were skilful in the extreme (Laura Jurd on trumpet, impossibly delicate in Mood Indigo), though they left the Black and Tan Fantasy a blowsy wreck, and didn't do that much to Mood Indigo itself once the tune finally arrived.

Finally came Harlem from Nu Civilisation and the BBC players combined: symphonic jazz, this, at a commodious length, with plenty of hot licks, tenderness too, and a conductor performing the Highland fling. The "American sound" has many more strands than this concert revealed, but it ended at least with a genuine bazooka, big, warm, and full-throated.