Susanna Mälkki's Prom with the BBC Symphony Orchestra opened with the premiere of From Trumpet by Ben Foskett. It is a piece of virtuosity and great charm, structured round a single rhythmic figure that accelerates and decelerates, attracting and shedding surface complexities as it goes. Three muted trumpets, swaggering and sinister, indicate changes of pace and mood before imposing a final stasis. Mälkki conducted it with grace and panache.

Thereafter, she turned her hand to two problematic masterpieces of 19th-century music. Beethoven's Fourth is the most elusive of his symphonies, a riddling score that plays games with expectations by promising a tragedy that turns out to be a bittersweet farce. Many conductors are defeated by it: Mälkki initially seemed intent on erasing its ambiguities by over-controlling the start, though she relaxed into the work's recklessness with elated accounts of both scherzo and finale.

Most performances of Berlioz's Te Deum, meanwhile, can only approximate the composer's intentions. It was conceived spatially, with the audience placed between choirs and orchestra at one end of the building, and an organ at the other. Like most venues, the Albert Hall can't accommodate the layout, with the result that we are not so much engulfed by its vast sonic barrage as assaulted by it. Nevertheless, it remains one of music's greatest examinations of the majesty and terror evoked by the idea of God. Mälkki's inexorable conducting, plus awesome singing from the combined forces of the Bach Choir, and the BBC Symphony and Crouch End Festival Choruses ensured that its impact was overwhelming.

The Proms continue until 12 September. Details: www.bbc.co.uk/proms