Written to commemorate the military losses of the French July Revolution of 1830, Berlioz's Grande Messe des Morts demands we remember the victims of war and political violence. In his memoirs, Berlioz said he composed the work "in a kind of fury", aiming to leave the listener "crushed by tremendous emotion". It petrified early audiences and remains arguably the most disturbing religious work ever composed.

It is difficult to perform. Berlioz conceived the work spatially, placing brass bands around the building to evoke God's judgment sounding from the edges of the universe. Maintaining ensemble during this apocalyptic eruption is well nigh impossible, particularly in a reverberant acoustic like St Paul's. Yan Pascal Tortelier's performance with the London Symphony Orchestra was a model of control and balance, however. The ensemble was faultless, with every fanfare chillingly precise. Throughout, Tortelier was alive to the work's rage, beauty and power, though the most unnerving sounds came in moments of bleak repose: trombones and flutes answered one another across a numbed void; muffled drums sounded like some cosmic heartbeat gradually weakening.

The choral singing, from the London Symphony Chorus and the London Philharmonic Choir, had a ferocious dignity, though the acoustic blunted some of Berlioz's more exacting polyphony, above all in the Rex Tremendae. The tenor soloist was Andrew Kennedy, rapt, ecstatic and offering us a brief vision of paradise amid the violence and despair.