Prom 53: BBC Philharmonic Orchestra / Ades, Royal Albert Hall, London

It would be interesting to discover quite how this distinctly odd Proms programme came about. For its first half (though originally announced as comprising its second), we were offered Sibelius's sprawling, five-movement symphony-cum-cantata Kullervo (1891-2), that astonishing flight of gaucherie and inspired boldness with which Sibelius first burst upon the musical world at 26.

And the second half opened with a pair of short orchestral spin-offs from The Trojans of Berlioz and closed with the 15-minute warning America: A Prophecy (1999) for mezzo, chorus and vast orchestra by the evening's conductor Thomas Adès.

Was Kullervo Adès's own choice, one wondered. He has conducted Sibelius sympathetically before. But here he often seemed nervous of those vast, almost minimalist tracts of ostinato rhythms with which Sibelius first unfolded his unique command of musical space-time – tending to push on too hastily much to the occasional confusion of the BBC Symphony Orchestra.

Fortunately, there were also the superbly drilled men of the Crouch End Festival and London Symphony Choruses to hold a rock-steady course through the ballad-like narration of the long central scena with the passionate Finnish baritone, Raimo Laukka, as the work's doomed Kalevalan hero. And conductor, chorus and orchestra rose finely to the cumulative funary declamations of the finale.

After Sibelius's as-yet less-than-surefire orchestration, the Berlioz extracts sounded positively burnished. These comprised the familiar "Trojan March," preceded by the far rarer "Lamento", taken from the additional Prologue Berlioz composed for a truncated production in 1863 – a strange, serpentine melody of ominous splendour that was punctuated by marmorial chords, which, more than anything else, set the mood for Adès's own unnerving "prophecy".

Commissioned by the New York Philharmonic for its AD 2000 celebrations, it was daring, indeed, for a 28-year-old Englishman to come up with something quite so unwelcome as America. This is ostensibly a setting of a prophecy of the destruction of the Mayan peoples by the invading Spanish Conquistadors. The work accordingly opens with "ancient" flute incantations, rapidly overtaken by the kind of searing and growling extremes of texture Adès has made his own, and shortly invaded by brutally triumphalist "Renaissance" brass.

But as the prophetess – in this performance the mesmerically vibratoless Susan Bickley – recurrently cuts into the music, it becomes evident that such phrases as "They will come from the east" and "On earth we shall burn" have a more immediate resonance. By the time the music expires in tone of black, ashen tragedy – a mood one has sensed behind a number of Adès's earlier scores – one is mindful not only of its uncanny pre-echo of 11 September, but, possibly, of things yet worse to come.