Bernstein's MASS, RFH review - polymorphousness in excelsis

Live exposure to centenary composer Leonard Bernstein's anything-goes monsterpiece of 1971, as with Britten's War Requiem of the previous decade, probably shouldn't happen more than once every ten years, if only because each performance has to be truly special.

Now, it seems, the world as a whole is closer to the collective breakdown characterised by Bernstein's constantly widening rift between the Latin words of the Christian Mass - many of them pre-recorded, in quadraphonic sound at the premiere - and the vernacular response which ranges from the desperate will to believe through cynicism and anger to rejection. Should it be an entirely American issue? As before, Kelly gives us images from the time of hope in JFK onwards, stylishly incorporated on screen canvasses by designer Michael Vale. They bring us as up to the minute as we can get; there is sight for one moment of the American Horror-Clown in Chief as the visuals rapidly fast-forward, and it is meant to pierce us, just when the crisis reaches its overwhelming zenith (caution: ear plugs needed, if only for three minutes). Given the specific framework, which involves one Groundhog Day return to flower-power ritual, I wonder how much the children and young adults this time connected with our own rift, where resistance isn't nearly as strong as it is in the States. But they certainly put their hearts and souls into the performance. It’s not the most precise or focused in its punch you’ll ever hear, but unless you fold your arms in response to Bernstein’s unusual openness, you can’t help but be moved.

This time the colossal role of the Celebrant, worn down by confrontational questioning to a tricky 14-minute nervous breakdown Bernstein calls “Fraction" and which surely owes something to Peter Grimes' mad scene, is taken by Paulo Szot (pictured above centre), born in Brazil to Polish émigré parents. He has what the part takes but rarely gets: an operatic baritone of warmth and power matched to the natural intensity of a show singer (his award-winning performance in South Pacific on Broadway really put him on the American map; he's found more often today singing Mozart). Rightly the vociferous-at-the-end but attentive audience reflecting the diversity on stage – where the National Youth Orchestra of Great Britain shared desks with players from the junior division of Chineke!, the pioneer of Black and Minority Ethnic (BME) players in classical music – went wildest for him. There was also huge enthusiasm for, and from, the ensemble of music-theatre students who make up the “Street People” (pictured above). It’s always a shame that you don’t find out who sings what there; Bernstein has some great music for them, including the poignant soprano solo “Thank you” and some properly rocked “tropes”, all charismatically taken. They also get the most striking lines, a quatrain given to Bernstein as a Christmas present by Paul Simon: “Half of the people are stoned/And the other half are waiting for the next election./Half the people are drowned/And the other half are swimming in the wrong direction.” Though wordwise the rest, by Bernstein and Steven Schwartz of Godspell fame, is rarely on the same level, the music fits it and everything's still topical; you only had to look at this bunch of young hopefuls to think of their schoolroom counterparts marching for gun control across the pond (heck, one boy even looked a bit like Parklander David Hogg).

Among the 500 performers, also including spirited diverse choirs coached by the now-ubiquitous Mary King, the dancers probably had the least good deal: their routines don’t chime with the very non-dancey orchestral interludes, where you really wanted to concentrate on the faces of the young players instead. But there was some deep and impassioned string playing – not easy for half the orchestra to see Alsop on the other side of the stage when visually blocked by the Street People on the central platform – and from the bluesy “voice from heaven” of the flutes in the initial “Simple Song” to the clarinets keeping the lonely Celebrant company, the woodwind playing always impressed. The three children taking up those initial “laudes” in the final road to recovery – Maia Greaves, Freddie and Leo Jemison (pictured above) – almost made me blub. Yes, it’s a sentimental apotheosis, but not mawkish; Bernstein now brings keening lines into the initially serene picture, and as in War Requiem there’s a calm final chorus (though without Britten’s last question mark). It's not so far from the ancient Greek theatre's "let us cry sorrow, sorrow, but let the good prevail". The Celebrant has picked himself up, dusted himself down and is ready to start all over again – but changed. Emotionally exhausted, we feel the same, if only for a while. Bravi tutti, and let's hear it for the achievements of the Jude Kelly era. One of her earliest London hits was a memorable production of Bernstein's On the Town at English National Opera, and it's appropriate that she should take her creative leave of the Southbank with a signature work highlighting the special good she's done here.

• One more performance of MASS at the Royal Festival Hall tonight
• Read more classical reviews on theartsdesk