Time was when Simon Rattle, a Liverpool lad good at playing drums, thought his destiny was to be a conductor. His main challenge, on top of mastering the task, would be to prise open the ears of know-what-I-like audiences. Instead, he has found himself the unofficially anointed only begotten saviour of the entire art form we call British classical music. It is an onerous burden. Five decades on, he alone guarantees headlines and column inches on issues that matter to the industry. We should be grateful he fights on.

In a speech from the platform (last Sunday, at a London Symphony Orchestra concert at the Barbican, issued as a media statement after), Rattle made his most urgent appeal yet: that those with power, specifically the BBC and Arts Council England, without any coherent plan, stop cutting away “at the flesh of our culture”. Lurking behind his words is the implication that whatever reprise BBC musicians or English National Opera have now, it is likely to be temporary. After the Proms, who knows? This is a battle for classical music’s survival.

If only the decision-makers – whoever they are – had been at ENO to experience Blue (2019), a much-performed American work, first seen at the Glimmerglass festival in upstate New York, being given its UK premiere. The libretto is by the playwright, director and actor Tazewell Thompson, with music by Jeanine Tesori, whose work spans Broadway musicals, film and opera. With a story about the lost lives of young Black men, a text in English and a score whose unusual contours are shaped by melodic ballads, as well as jazz, gospel and blues, the work could hardly have ticked more diversity boxes.

Of greater importance, Blue is a rewarding show, expertly sung, powerful in impact. By chance timing, it offers a sharp contrast to Kaija Saariaho’s Innocence at the Royal Opera House, reviewed last week. The works touch on similar issues, but Blue, full of gentle humour and humanity, arguably makes its point more acutely. In the fickle business of creativity, a work can be uneven yet still triumph. The ponderous start, despite luscious singing from a sassy trio of “girlfriends” (Chanáe Curtis, Sarah-Jane Lewis and ENO Harewood artist Idunnu Münch), is followed by an even slower scene in a Harlem maternity ward. This soon yields to the work’s central story: a relationship between a father who is a police officer and his son, a talented teenager engaged in Black activism and peaceful protest, who can hardly bear having a cop for a parent. A tragedy unfolds.

The American bass Kenneth Kellogg as the father, a role full of pain, anger and kindness, and the South African tenor Zwakele Tshabalala (also a Harewood artist) as the son, sang with bristling, heartfelt intensity. So too did the British soprano Nadine Benjamin, as the mother. The only complaint is that the work’s structure gives this most engaging performer too little time on stage. The Trinidadian tenor Ronald Samm (an unforgettable Otello with Birmingham Opera Company in 2009), as the reverend, led the small ensemble of menfolk, completing a watertight cast.

The simple but highly skilful geometric staging – a revolving rectangle inscribed in a circle – is directed by Tinuke Craig, designed by Alex Lowde, with grainy, atmospheric video of Harlem life by Ravi Deepres. Matthew Kofi Waldren conducted with evident love as well as efficiency and care. As part of the English National Opera season mix, this is a smart choice. Far from docuopera, it looks at Black lives from the inside: a family sitting together at the table and trying to deal with life.

Next door, on Monday night, a packed St Martin-in-the-Fields welcomed the Monteverdi Choir, the English Baroque Soloists and their founder-conductor, John Eliot Gardiner, there to celebrate his 80th birthday with a performance of Bach’s Mass in B Minor. In addition to two recordings, Gardiner has performed this Everest, as he calls it, numerous times. He began his pioneering advocacy for historically informed performance as a student at Cambridge in the 1960s. His has been a tempestuous and brilliant career, not short of controversy, but few rival him in energy, curiosity, dedication, in every corner of the repertoire, with Bach at the centre.

From the opening Kyrie of the mass, urgency and volume won out over doubt. The Monteverdi Choir hurled out the great choruses as if their lives were at stake, every word clear and committed, the counterpoint untangled and fluid, as if easy – which it never is. The English Baroque Soloists excelled, with special praise to trumpets, oboes, flutes, continuo and leader, violinist Kati Debretzeni. Among the fine soloists, leading from the chorus, tenor Nick Pritchard brought welcome stillness to the Benedictus, countertenor Reginald Mobley was imaginative and poetic in the Agnus Dei, and bass baritone Alex Ashworth had quiet nobility in Et in Spiritum Sanctum.

Meaty, deeply coloured, this robust account was less about light and shade than blinding dazzle or darkness visible. By the end, Gardiner, reasonably, looked shattered. But he had danced his way through the performance, shedding his years and paying homage to a composer so closely associated with him. The standing ovation and cheers were long and loud. Broadcast live, the performance is available on BBC Sounds. Many happy returns, John Eliot Gardiner!

Star ratings (our of five)
Blue ★★★★
Mass in B Minor ★★★★

• Blue is at the Coliseum, London, until 4 May