Never have I experienced a silence so full of meaning. Neither have I experienced the audience at the Royal Albert Hall remaining so still. As the final, hushed words Requiescant in pace. Amen (May they rest in peace. Amen) died away, conductor Andris Nelsons held tightly onto the silence that followed. But this silence was not forced or used superficially to add meaning. It was the inevitable response of an audience moved by an extraordinarily sensitive performance. It was one of the longest held silences before applause, and one of the tensest and most meaningful moments I have ever felt.

An immediate applause after Britten’s hugely poignant War Requiem would have been inappropriate. Composed to celebrate the consecration of Coventry Cathedral in 1962, which had rebuilt after being destroyed in World War II, the War Requiem is a statement of outrage against war. Interspersed between the texts of the Requiem Mass are war poems by Wilfred Owen conveying anger over the fate of young men sent to their deaths. For the different parts of the text, Britten divided his performing forces into three. Firstly, baritone and tenor soloists accompanied by a chamber orchestra represent two soldiers as they sing Owen’s poetry. Secondly, a soprano soloist, large chorus and full symphony orchestra sing the liturgical texts. Lastly, off-stage children’s voices accompanied by organ sound are a distant sound divorced from human experience.

Given the importance of the words, it might have been easy for the City of Birmingham Symphony Orchestra to become complacent. They mostly accompanied and there were few moments where the orchestra took a central role. Yet the CBSO knew how to accompany. They supported the singers and allowed them to speak, but they also infused their playing with a buzzing energy. Particular praise must go to the fearless playing of timpanist Patrick King. Watching him smash down onto his instrument in the Dies irae added immensely to the drama of this downright terrifying movement.

The audience were treated to three very capable soloists. Soprano Susan Gritton sang through her awkward leaps with ease. Her voice soared wonderfully above the chorus. On high notes, she was glorious but careful not to over-indulge. Meanwhile, tenor Toby Spence and baritone Hanno Müller-Brachman expressed all facets of Owen’s text. Müller-Brachmann had a sad deepness in his tone that was especially fitting for Owen’s poetry. Their voices complemented each other well, and their coming together for “When lo! An angel called him out of heaven” was revelatory. When the CBSO Children’s Chorus entered soon after, Nelsons' mediation between the two forces was controlled. The harsh reality of the soldiers from the male soloists was juxtaposed with the other-worldly children’s choir to great effect. Situated far away in the Gallery, the children’s choir were not only literally distant, they sounded unreal too, as though coming from the beyond.

If the children’s choir were unearthly, the BBC Proms Youth Choir was striking for their ability to portray unease. This was important for the work’s opening, when the music is rather stationary. Yet the disquiet produced by the chorus’ chilling softness kept the music engaging by forcing the audience to listen with rapt attention. Whilst their handling of quiet moments was captivating, they could be tremendous too. With full forces in the wrathful Dies irae the chorus reached a threateningly sublime level, and were glorious for Hosanna in excelsis in the Sanctus movement.

With the three performing forces, Nelsons was left the difficult task of mediating between them. As a conductor, he was thrilling to watch. But for Nelsons this was not a performance for himself, but for something bigger and greater. Particularly astonishing was his handling of the different forces in the final movement, Libera me (Deliver me). The held notes in the chamber orchestra that accompanied the tenor and baritone solos created a haunting stillness, due to the concentrated playing that Nelsons enticed from his players. Though only a single voice and a few players, these final solos were gripping.

But it was when all three performing forces joined together during the tenor and baritone’s last hopeful plea “Let us sleep now” that the performance transcended. Their duet was a comforting lullaby, beautiful and tranquil. Yet the chorus were given the final words. As the work drew to its close, they were incredibly responsive to even the tiniest gesture from Nelsons. This concentration transmitted into the audience’s response, as they hung onto every last moment of the chorus’ soft, transcendental sound. They still listened keenly, even as the sound faded into profound silence. It was an unbelievable and perhaps unrepeatable close.

William Mann wrote in The Times following the War Requiem’s première that “every performance it is given ought to be a momentous occasion”. Last night’s performance certainly was, and one of the few concerts that I have felt privileged to attend.