Thomas Adès must be the only modernist composer happy to conduct Borodin's knee-slapping Polovtsian Dances. Adès loves the grand noise, even the cornball, as his conducting gestures show: baton scything through long grass, body imploring, passion quivering from every pore. Besides conducting without shame, he knows how to programme.

The opening instalment of Saturday's Prom tossed us into the cauldron of Mussorgsky's A Night on a Bare Mountain, in its opera version, then simmered down only slightly with gobbets from Boris Godunov, conveyed with that glowering force guaranteed if you hire the bass voice of John Tomlinson. The finale prefaced the Polovtsian knees-up with Prokofiev's glittering first piano concerto, dispatched by Louis Lortie with an admirable light touch.

Yet it was the middle attraction that really fascinated: Adès's magnificent Tevot, two years old, a one-movement kaleidoscope from a composer who now handles orchestral writing better than anyone else in Britain. The work's meaning? That is up for discussion.

There's nothing elusive about the emotions engendered by its fissured tapestries of sounds (airy, spiky, hiccupping, ghostly). Journey's end is a comforting motif, curling down from the top register in a sequence that knocks the ground from those who claim contemporary music lacks heart (or tunes). The City of Birmingham Symphony Orchestra's delivery was gleaming and exultant.

Some of their sheen could have benefited Friday's painterly Prom, with Thierry Fischer and the BBC National Orchestra of Wales. Dutiful is the killer word for their Pictures at an Exhibition and Debussy's Nocturnes. Still, they showed greater mettle in the gnomic fancy and brilliance of Simon Holt's Troubled Light, a Proms commission. The orchestral medium has only recently become Holt's friend, and he is still in the grip of the lover's swoon. Wide ranging textures jostle or get punctured by bass drum thumps; only in the final five minutes are elements co-ordinated and threads tied. The jagged diversity is arresting; appropriate, too, given the title's poaching of Goethe's description of colour. A welcome new piece.

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