“We’re giving people permission to feel uncomfortable,” says American playwright Dael Orlandersmith of Until The Flood, which addresses the 2014 shooting of African-American teenager Michael Brown in Ferguson, Missouri, by white policer officer Darren Wilson – igniting Black Lives Matter-propelled social unrest.

A year later, the Repertory Theater of St Louis commissioned Orlandersmith to write a play, as a way of talking about a subject that still divided a community. "St Louis is one of the most segregated cities in the US," she explains. "For three days, I interviewed around 80 people in this little restaurant, and from that, I took some lines verbatim, and created composite figures."

Orlandersmith, who plays all eight characters herself, felt it was important not to focus on "who did what where, but how this shooting affected people's lives." Though race is a key facet, "it's the whole human experience. Michael and Darren were both born to young women who didn't know how to take care of them.

"Darren's mother was a grifter, and when she died at 34 (in weird circumstances), her third husband told a teenage Darren 'You've got to go'.

"Michael's mother had him at 16, her mother had her at 16. She was moving him all over the place. So that's a catalyst to question the life choices that you're proud of or not, the sociological elements, and the sins of the mother and father."

Orlandersmith was careful not to caricature - "I had to love every character." That's more challenging, she admits, in "certain volatile moments" with her interviewees, but "not every white person had a 'racist' view. And even if someone is racist, my job as a theatre worker is to find out why.

"Not everyone was happy with every part, because people want their own sense of justice, at the expense of another's truth. I won't convey someone's argument, but I will portray it, along with others. If you look back to Arthur Miller, he was inspired by real people, but he never beat you over the head with messages - when plays do that, I draw away. I really wanted to make this a theatrical experience."

But Orlandersmith is also aware "this involves real human beings - I'll suddenly remember an expression on someone's face when I'm performing. Like there was this young boy who was very funny and said 'If you need a rapper for your play, I'll do it!' He'd suffered a history of abuse and spoke about that. When you listen, people begin to tell you other facets of their lives.

"I hope this piece invokes and provokes thought and conversation. I was a little kid in the sixties, and there's a certain upheaval right now that feels like aspects of history are repeating. We're learning a different language and the demographics are changing - as they should. But there's a lot of fear around that. Hopefully, when people become settled, they'll be willing to ask questions and gain understanding."

As for how British audiences will respond to Until The Flood, Orlandersmith says it's "a human tale - everyone has a form of bias, or they question who they are and where they belong. Like the London riots, or with Brexit, people are now being treated differently because they're originally from Poland or somewhere."

Orlandersmith notes she's "drawn to dark subjects" in her work, "that shadow self within." However, she's frustrated that artists of colour are still limited in terms of what subjects are commissioned. "I'm black and female, I know what that is, but let me write about other things too. When I teach, I say just tell the stories you want to tell. Don't play into that bias or feel you have to 'represent'."

Orlandersmith's own writing began because, as "a tall, big black woman, there weren't the roles for me. It was welfare mother or prostitute." She's encouraged by the greater diversity now, though there's still work to do. "One day, it won't matter about race or gender, just great stories. I'm not writing or performing for any one audience; it's for everyone. The more we listen to each other, especially those who are different, the better our world becomes."

Until The Flood runs at Arcola Theatre between September 4 and 28. For more details and tickets, click here.