As leaving parties go, Mahler 8 is a tough one to organise. To mark the end of Thomas Søndergård’s six years at the helm of the BBC National Orchestra of Wales, invitations went out to eight soloists, five choirs and a supersized orchestra, bringing together 675 performers for the ultimate big finish in Mahler’s most decadent symphony.

Morris Robinson, Quinn Kelsey and Thomas Søndergård
© BBC | Chris Christodoulou

The symphony is an unabashed monster of a piece, a Wagnerian epic in both scale and scope, shrewdly juxtaposing a medieval Pentecostal hymn with the last pages of Goethe’s Faust. Tonight’s performance also made a fascinating sequel to the previous night’s Beethoven 9 in a mammoth weekend of choral indulgence at the Proms. Here it was the slow-burning drama of Faust’s redemption which gave the greatest thrills after a dashing but occasionally nervy Veni creator spiritus, Søndergård’s meticulously weighted pacing giving a tantalising hint of what a Mahler symphony might have looked like.

With choristers perched from stage to rafters, the smaller first part of the symphony erupted from the stage with vigorous tempo and dynamics. Acoustic balance in the Royal Albert Hall is hugely influenced by one’s position in its cavernous auditorium, but from my seat the soloists were occasionally drowned by the massed forces of the Southend Boys’ and Girls’ Choirs, London and BBC Symphony Choruses and BBC National Chorus of Wales. The Latin text was not always entirely clear, but its meaning certainly was, unfolding in a scrapbook of thrilling moments: Accende lumen sensibus went off like a rocket with compelling tension held through the ensuing fugue, and a titanic, double-cymballed recapitulation led the music promptly towards a blazing halfway point in the symphony. In this renaissance of inter-movement applause at the Proms, I was surprised by the lack of audience reaction at this point; perhaps everyone was a little breathless.

BBC NOW and choirs
© BBC | Chris Christodoulou

Part Two unfolded with ever-growing excitement from the wonderfully operatic prelude on the bleak mountainside to the celestial finale. The hushed, staccato whispers of the former scene bounced back in echo form from the contralateral side of the organ in a shrewd move of stage management. Elsewhere the Younger Angels sang with enough gentle innocence to conjure up the composer’s Fourth Symphony and its child’s eye view of heaven, and the first, pianissimo invocation of the Chorus Mysticus was spine tingling with such resonant bass voices.

The soloists were uniformly strong, each giving their contribution in a manner which brought to mind the song prize in the biennial sing-off in the orchestra’s home city. The most memorably brilliant was Simon O’Neill as Doctor Marianus. His huge, pure sound filled the hall seemingly effortlessly from his first entry, and “Blicket auf”, inviting the Chorus Mysticus to the party, was immensely stirring in the Gretchen theme. Though just two lines long, Joélle Harvey’s contribution was similarly magnificent, drifting down gently from the dizzying heights of the gallery, where she was just perceptible in the shadows. Gretchen, transformed into Una Poenitentium, sang with not a hard edge in sight but irresistably imploring “Neige, neige!” with the harps. Pater Ecstaticus (Quinn Kelsey) set the tone for the cantata in full and attractive voice, and Morris Robinson’s gravelly bass made for an excellent Pater Profundus, convincingly giving the illusion of singing from the depths. Tamara Wilson, Marianne Beate Kielland and Claudia Huckle combined beautifully in their brief trio as Magna Peccatrix, Mulier Samaritana and Maria Aegyptiaca.

Søndergård’s ability to highlight the subtlest details in Mahler’s idiosyncratic moments of chamber writing were expertly realised by his orchestra, and in the tutti passages he drew out some horn playing of blazing intensity. The strings brought the themes of redemption to life in their elegantly soft legato, and the floor shook as the Danish conductor forged breathlessly ahead through the epic last minutes of the symphony. The offstage brass avoided any ensemble issues perched in the second tier of boxes on the left of the stage, but from here they didn’t project as well as they have done from elsewhere in the hall on other occasions. There can’t be many better ways to bow out of a principal conductorship, though, as the capacity audience seemed to agree in a prolonged ovation.