I WONDER what Michael Tippett would have made of our times. What kind of lush, kinetic music he would have summoned in response to a geopolitics of post-truths and hypernormalised hate speech. This was the composer who began work on a pacifist oratorio the day Britain declared war on Germany in 1939, who later went to prison as a conscientious objector. He made the opening words of that oratorio as bleak and urgent as the way he was feeling: “The world turns on its dark side,” sings the chorus.

One of my favourite Tippett quotes relates the artists of today – his day, our day – to an age-old tradition that, he said, “goes back into prehistory and will go forward into the unknown future. This tradition is to create images from the depths of the imagination and to give them form. […] Images of vigour for a decadent period, images of calm for one too violent. Images of reconciliation for worlds torn by division. And in an age of mediocrity and shattered dreams, images of abounding, generous, exuberant beauty.”

In its own way Tippett’s music is exuberant and beautiful. A Child of Our Time is based on the events of Kristallnacht and traces the course that one brutal act of bigotry can set in motion. At its heart are five Negro spirituals – 19th century American slave songs whose pain and defiance resonated for a wartime audience in the 1940s and still resonate 70 years later. This summer, a fortnight after the EU referendum, the conductor Mark Wigglesworth wrote that “for decades we have listened to A Child of Our Time as a reminder, a lesson we may have liked to imagine we had learned. But despite Tippett making it abundantly clear that his piece is an attack on racial prejudice, bigotry and xenophobia, it seems we have been complacent in ignoring its warnings.”

We shouldn’t be complacent about Tippett for many reasons. During his lifetime he was overshadowed by Benjamin Britten, eight years his junior and the venerated voice of 20th century English music. He was eyed with suspicion for his homosexuality and humanism, for his bold clothes and his habit of keeping a Jungian dream diary. He confused people because he wrote music that was subtle (sometimes) and sensuous but still politically ultra-charged.

Maybe his outsider position gave him a freedom to get on with his own aesthetic ideas and to question what kind of subjects were acceptable to write about in classical music and in what kind of language. He wrote his own opera librettos, some of which were hopeless, but at least he tried. He thought a lot about the role and ethics of art in society and came out feeling hopeful. “He knew that music might be powerless to change politics,” writes the conductor David Robertson, “but that it could effect seismic shifts in people.” Seismic shifts: surely now’s the time.

This week the BBC Scottish Symphony Orchestra begins a cycle of Tippett’s symphonies. These are rarely played and fascinating pieces that date from 1945 to 1981 and articulate Tippett’s astute engagement with the world around him. He began work on the First while incarcerated in Wormwood Scrubs Prison in 1943. The Second speaks with the vigour and bright new optimism of the late 1950s. The Third quotes Beethoven’s Ninth then a soprano clatters in singing the blues. According to David Robertson, “a major strength of the Third is that it poses the question: ‘Yes, Beethoven is indeed beautiful, but can we listen to the Ode to Joy and not be aware – after the 20th century’s bloodletting and the 21st century’s new ability to terrorise – that the only Brotherhood of Man we will have is the one we ourselves are responsible for?’” Finally, Tippett called his Fourth and last symphony a “birth to death piece” and included in the score the sound of amplified human breathing. The piece ends on an unaccompanied intake of breath.

Martyn Brabbins conducts the BBCSSO’s Tippett performances, and when I spoke to him about it he revealed that the orchestra has been granted permission to add one further work to the cycle. It’s the composer’s early symphonic embryo, withdrawn after its first performance. When Brabbins and the BBCSSO record it next year along with the four official symphonies, it will be its first recording. “I asked the Michael Tippett Musical Foundation whether they would let us do it,” Brabbins says. “There were long deliberations. They took it seriously and we took it seriously. Then they said yes.”

So what’s it like? “You can tell it’s not the mature Tippett – though who can say what really is the mature Tippett? It has obvious fingerprints of Beethoven and Sibelius, he just hadn’t assimilated those fingerprints into his own style yet. I really think that hearing it will shed new light on Tippett. It will help complete our understanding of his early chapter.”

Brabbins explains that he knew the composer personally. “Well, only a little, and I wish I’d known him better. I conducted his music at the Proms and the Wigmore Hall. He was always a delight to work with. Such charm. An incredibly positive life force. Similar to Max [Peter Maxwell Davies] in that respect – something to do with that lovely, sweet, youthful spirit. He was extravagant in his choice of clothing. All those striped tops! What I regret is that I never spoke to him about his withdrawn symphony. We need to make more of people while they are still with us.”

What would Tippett have thought about the symphony he didn’t want people to hear – he regarded it as immature and overly influenced by Sibelius – now being performed and recorded? “Well…” Brabbins pauses. “I suppose he might have thought we were being a bit cheeky. He had a clause in his will that more or less said ‘just leave it alone now’. But, well, we’ve decided it’s worth hearing. Personally I feel there is more to be gained than lost.”

We’ll have to wait until next season to find out. For now, let’s ponder the closing words of Tippett’s first opera, The Midsummer Marriage, which is a couplet from WB Yeats: “All things fall and are built again/ And those that build them again are gay.” Or indeed the words Tippett himself told an audience in Liverpool before the premiere of his First Symphony on 10 November 1945: “Hang on tight. It comes out all right in the end.”

Martyn Brabbins conducts Tippett’s First Symphony tomorrow night at City Halls. He conducts the Second Symphony on February 9, 2017. The Third and Fourth symphonies, and the early withdrawn symphony, will be performed during the BBCSSO’s 2017-18 season