On 4 August 1914, Britain declared itself at war. Exactly a century later, the British institution that is the BBC Proms commemorated this monumental historical event with a sombre yet spectacular late night concert featuring the music of the late John Tavener. Peter Phillips directed the Tallis Scholars and the Heath Quartet in what was an extraordinarily powerful, yet predominantly peaceful, event of solemn remembrance – and resplendent singing.

Luminosity was a central theme of this concert: at the end, Prommers illuminated (electric) candles as the house lights were dimmed; at the beginning, powerful evocations of light were made in the choir’s opening passages of Ikon of Light; and throughout, the Tallis Scholars sang with such radiance as to illuminate the Royal Albert Hall with the unworldly sound of Tavener’s music. Both Ikon of Light and Requiem Fragments – a BBC Commision receiving its world première in this Prom – were written for the Tallis Scholars, and Tavener knew to exploit the polyphonic expertise and technical capabilities of Phillips’ scholarly bunch. The Heath Quartet added their faultless tones to the spectrum, performing the composer’s peculiar brand of slow, imitative, understated string writing with tireless concentration of mind and sound. Nevertheless, the concert ended in darkness; having recited Wilfred Owen’s Anthem for Doomed Youth, actor Samuel West bid the Prommers extinguish their lights for a moment of reflection on the cataclysmic events 100 years ago. The contrast between light and dark was highly charged and, as might be expected, exceptionally moving.

Tavener’s renowned mysticism, and the centrality of the Orthodox faith to his work, emanates from every aspect of Ikon of Light. Structured as a polyptych, it is a seven-movement piece centred around a “Mystical Prayer to the Holy Spirit” by turn-of-the-millenium Byzantine monk-poet Symeon the New Theologian: an invocation to the Divine every line of which begins with the word “Elthé” (“Come”). There is extensive use of Tavener’s version of Byzantine liturgical chant throughout the piece (as there is throughout his œuvre), usually set in the midst of a cluster pedal, but occasionally treated to the kind of simultaneous inversion that makes passages in The Lamb so satisfyingly otherworldly. The resultant bi-modality of this musical mirroring was a particular feature of the “Trisaghion” movements (3 and 5), in which it was enjoyed by both the string trio and the choir in turn. The instruments and singers were for the most part segregated, the trio introducing or concluding the separate movements and creating a beautiful contrast in timbre upon each appearance, the warmth of their strings dissolving the austerity of the crystalline choral passages.

The Mystical Prayer itself began with a high chant-like motive sung delightfully delicately by a few sopranos as the others held a pianissimo cluster chord around it; this was then repeated octaves below by each part, ending with ridiculously low basses, musically mooing away beneath the stave. This formula was repeated, but with the parts holding their cluster-chords across into the lower iterations of the melody: a fantastic way to build texture, but cruel for those sopranos charged with the highest notes! They did exceptionally well, however; I could never tire of the Scholars’ sopranos spotless, slightly reedy – almost siren-like, or mermaid-ish – sound, reminiscent in their upwards runs of the renaissance polyphony for which they are so lauded. I couldn’t quite say the same of the basses, whose thickness occasionally bordered on bellowing.

Theirs was a much gentler sound as they began Requiem Fragments with the spiritually significant syllable “Om”, which provided a drone over which the Heath Quartet (now back to its full complement) wound their exquisite measured contrapuntal texture. The ensuing Requiem aeternam was majestically peaceful in its consonant homophony. Further passages from the Requiem Mass appeared simultaneously, thanks to a bifurcated choir, with words drawn from Hindu sources: Brahma/Te decet; Atma/Sanctus. The introduction of two trombones in the Kyrie opened up a whole new, almost redemptive soundworld, although they did little more than mark the beat under the sustained chords of the choir. However, the climax of the piece – and the concert – came as soprano Carolyn Sampson, perched behind Henry Wood, sang a mesmerising solo; her voice, singing the words “Manikarnika” (the name of a Hindu shrine and place of cremation on the Ganges) and “Mahapralaya” (the reabsorbtion of everything into the Divine Being) soared sublimely over what it said in the programme was an eleven-part canon, but what sounded to me simply a heavenly, nebulous consonance, ever shifting and yet in perfect stasis.

Transcendence is a word overused in relation to Tavener’s music, but here, it must not be avoided. All that followed – the final Requiem section, the fake candles, the hard-hitting poetry, and the darkness – all was infused with the iridescence of that sensational moment of Mahapralaya.