“I HAVEN'T been so angry for a long time,” says composer Mark-Anthony Turnage. His voice is laconic, as though the statement is too obvious to even bother. “I was angry during the Thatcher years. Now I’ve got my anger back.”

There is older anger afoot. Oedipus is raging in a greasy spoon. We already know how the story ends: he’ll commit murder, he’ll accidentally sleep with his mother, he’ll gouge out his own eyes. This is the East End of London in the late 1980s, Thatcher’s Britain, a backdrop of football chants and social depravity. Oedipus – let’s call him Eddy, the protagonist of Steven Berkoff’s play Greek – aspires to better but fate pulls him back. “Fate,” his mum warns him, “makes us play the roles we’re cast.”

Turnage was in his mid-20s when his teacher Hans Werner Henze suggested he write a chamber opera for the Munich Biennial. He had never been interested in opera – he thought the form was bourgeois, elitist, out of touch with people like him who had grown up in working class Essex. But Henze was looking for a game-changer and he got one. Turnage decided to set Berkoff’s smart, mouthy play, and the first Decca recording of the opera was issued with a language warning: “may offend”.

The premiere took place in Germany in 1988, surely a first for an opera in broad cockney. The UK premiere was at the Edinburgh International Festival the same summer and clearly it chimed with the times. “We hoped it would cause an uproar,” reflected Jonathan Moore, director of the original production. “A first-night punch-up like that inspired by Stravinsky’s Rite of Spring. Instead, we got a standing ovation for 12 minutes.”

Now Greek returns to Edinburgh in a new co-production between Scottish Opera and Opera Ventures directed by Joe Hill-Gibbins. Is its anger more relevant than ever?

“I get those questions every time it gets revived,” Turnage sighs – and Greek has been revived a lot, multiple different productions in multiple different countries. The last time it came to Scotland was a Music Theatre Wales/Scottish Opera co-production in 2011 while riots were sparking off from Tottenham across England.

“Part of me wishes the thing would become irrelevant,” Turnage admits. “Wouldn’t it be much nicer if we could just move on and declare it a period piece? But yes, just look at the past year. Look at Grenfell. Unfortunately it does feel more timely than ever.”

A lot has happened for Turnage personally since Greek first rocked the opera world and branded him the next generation of badass British composer, in the footsteps of Peter Maxwell Davies and Harrison Birtwistle. Like them, he slid his troublemaking persona into establishment roles, writing big Proms pieces as resident composer with major UK orchestras. He wrote more opera, too, including The Silver Tassie for English National Opera (2000) and Anna Nicole for the Royal Opera (2011), the latter based on the life of the Playboy model who married an 89-year-old billionaire and died from a drug overdose in a Florida hotel.

Building on the outwardly outrageous but often very lyrical sound world he invented for Greek, Turnage crafted a house style that was brazen and bristling, that got ensembles riffing to jazz and funk and pop rhythms. There was Blood on the Floor (1996) for Ensemble Modern and jazzers John Scofield, Peter Erskine and Martin Robertson; there was Twisted Blues with Twisted Ballad (2008), in which a string quartet weaves in Led Zeppelin songs Dazed and Confused and Stairway to Heaven; there was the Proms piece Hammered Out (2010), in which the BBC Symphony Orchestra blasted out chunks of Beyoncé’s Single Ladies (Put a Ring on It).

“All of my music is political,” he says. “I can’t deal with what [the director] Richard Jones calls classy snooze. I have to go for something that sustains my interest.” And if anything, he says, “I get more leftwing as I get older.”

If he were to write Greek today, would he write the same piece? “No.” A pause. “Which is a shame. I mean, the rawness. The f**k-you-ness of it. That’s actually what I felt at the time. When I wrote Greek, I didn’t really know what I was doing. I know it sounds slapdash but it wasn’t – I worked really hard at it, but at that point I hadn’t written anything that lasted more than 12 minutes. I was intimidated but I thought, ‘f**k it’. I have more inhibitions now and that probably means the music would be less raw. The rough edges would be softened off. I look back at it and think, ‘did I really do that?!’”

Turnage was a reluctant opera composer from the start and some of his reservations around class and entitlement still linger. He has a new piece on the way for Covent Garden’s 2020-21 season, and although he no longer believes the form itself is out of touch – his own operas have disproved that – the question of audience demographic still sticks in his throat.

“I still feel uncomfortable sitting among the audience I’m writing for,” he says. “I try not to go to the bathroom during the interval – I’ve overheard some horrible things. I often end up sitting there thinking, ‘I’ve got absolutely nothing in common with people who go to my stuff’.”

“And yet most of the management and musicians and singers are really fabulous people who genuinely give a s**t about the music,” he clarifies. ”I’ve seen it at Covent Garden, at Holland Park, at Glyndebourne. These places are amazingly run and not stuffy at all. Unfortunately most of the audience doesn’t live up to it.”

Turnage isn’t one for false optimism or gushy classical music PR. He believes that, if anything, attitudes have worsened over the 30 years he’s been avoiding opera house loos. He believes that, had he grown up in today’s Britain, with its cuts to free music education, rise in child poverty and social mobility on the decline, he would never have become a composer.

“I think back to studying at the Royal College of Music with people like Robert Irvine and Will Conway” – two cellists who came from working class backgrounds in Glasgow. “I just don’t think the equivalent kids would make it to music college now. The means of access are disappearing. If we’re not very careful, classical music will end up entirely out of reach for most people. I teach at the Royal College. I see very few students from working class backgrounds.”

Do pieces like Greek have the power to change things?

“No,” he says. Again, that laconicism. “I believe in art but I’m not that optimistic. People are too lethargic. That’s what happened with Brexit. People didn’t care enough. People sat down and let it all happen. They come to the opera and they’re happy if they get a drink and a posh seat.” Why revive it, then? “I didn’t expect it to be revived.”

Why keep writing operas? “Because people ask me to. And,” he concedes, “because I have a compulsion. Because I’m still angry.”

Greek is at the Festival Theatre, Edinburgh, on August 5 & 6.