The Saturday night of Bank Holiday weekend of the 2017 Proms found a hall at least half-empty; a sure sign that not one of Tchaikovsky, Brahms or Mozart was to feature in the programme. This prom, entitled The Bohemian Reformation and containing just Czech music, was a concert that appeared to entice either specialists or those with esoteric preferences; in their totality they filled just half the seats. And yet rambunctious rounds of the recipients’ applause made-up for all those hollow posts. Through this barometer alone, the lack of audience would not have been detectable.

Maestro Jakub Hrůša began with a traditional a cappella battle hymn, the Hussite chorale "Ktož jsú Boži bojovníci" (You Who Are Warriors of God). It was this theme that made an appearance throughout all subsequent pieces performed in the prom – both musically and conceptually. The men’s voices of the BBC singers performed this two-minute work with an uncomprisingly authoritative, vigorous and yet solemn assumption of these trenchant harmonies. With crystal-clear diction and crisp, hissing consonants, their enunciation of these verses was both a caution and an idolatry prayer; the basses serving as the first whilst tenors countered austerity with their reverent God-fuelled submission.

Then Hrůša undertook the two least known symphonic poems from Smetana’s Má vlast: Tábor and Blaník. Here the listeners were ushered into a great Bohemian fair as motley and as multi-faceted as the Prague Christmas Markets; one with as many different sounds, textures and colours as a fair has stalls. Every section of this orchestra was not a collection of noises or collage of pictures: it was a one-pane dimension. There were flake-sized fragments of bow strokes that came off as easily as a thin curl of carved appled skin falls from a knife. Flutes were the airy breeze conveyed over the Moldau – though the titular work was itself absent. With strings that could be as quiet and scrambling as the sound of a scurrying pen and flutes whose timid entrances could be as slow as the descent of the last raindrop sliding down a window, Hrůša’s innovative choices across texture and dynamics were juicily unpredictable. These two parts of Má vlast rendered no memorable melody – these are not tunes one takes home – yet under Hrůša’s baton phrases alternated between majesty and pompousness and transmuted conflict into somnolent peace.

This musical picture came apart at the seams with the next work: Martinů’s Field Mass. Bereft of the majority of instruments that featured in Má vlast, Hrůša was left with men’s voices, piano, a pump organ, woodwind and occasional percussion. In this nihilistic atmosphere, trumpets dwindled in long drawn-out, lonely phrases. The pump organ played disruptive chords that mirrored sounds of tumbling disassembled homes, rubble and artefacts of war. That Romantic paysage of Smetana’s had been swamped with the remains of a fight, namely, the Czechs’ plight in World War II. The orchestra became unrecognisable. Baritone Svatopluk Sem performed his vocal line with bold and rigid determination, never allowing any purity of sound to sway. He easily evoked the gut-wrenching ambition of a nascent soldier eager to enlist.

The calm after the storm arrived with Dvořák’s Hussite Overture. Timpani snaps were measured, strings strokes were so gentle that they sounded fearful they might wake somebody up. All of a sudden this was twisted into one fortissimo outcry of victory. Compared to Martinů, the little tweets of birdsong on the flutes and melting harmony of brass and strings felt almost disconcerting – in the most impeccable of ways.

Janáček’s Suite from The Excursions of Mr Brouček introduced a wailing oboe, alarming tolling bells and brass that had been fastened in a strange cathartic cleansing. All of this was then substituted with Josef Suk’s symphonic poem Prague. Here the random interspersion of brass notes – which risked creating chaos – only forged deliberate, preconceived, expected disarray. Key changes on strings were both conspicuous and simultaneously subtle; effectuated with accentuation that effused nobility – and not the usual coarseness heard across such modulations. Rhythms were as varying and decided as syllabic stress in the recitation of poetry. What Hrůša does with musical phrases is not so dissimilar to the practice of scansion: his designation of accents is often unsurpassable.

This was playing of an exactness so fine that at times it felt beyond human. Hrůša assumed rarely heard, rarely popular Czech works with a conducting that transplanted them onto another level of interpretation; an unearthly one. The repetition of a single, brisk motif underwent transformation with every new utterance. This was interpretative stylistic choices at an advanced level; a feat to which only maestri with inarguable taste and intuition can climb. In a time when most great 20th-century maestros have already passed, Hrůša lends a definition to sublime performance for this current era.