It is a busy, bright afternoon on London’s Southbank, when I meet the lower-case-preferring dramatist debbie tucker green. We’re here to discuss her latest film, ear for eye, which will premiere at the BFI’s London film festival, shortly followed by its broadcast on BBC Two. All around us is excited chatter and clinking crockery, as the festival swings into gear.

tucker green does not find that distracting. For her, tuning out industry noise has become something of a creative superpower. “It’s almost like I have to be quiet to hear what’s going on in here,” she says, tapping the side of her head with her index finger. “I have to have clarity on what’s gonna come out.”

Rarely granting interviews probably also helps with that. This will be her first conversation with a journalist in six years. And it’s fair to say the work speaks for itself: since 2000, tucker green has written, and often directed, 13 enthralling, politically engaged plays, including the Olivier award-winning born bad. In 2011, she successfully adapted her 2008 one-woman play, random, into a Channel 4 drama, featuring a pre-fame Daniel Kaluuya and a virtuoso performance from tucker green’s frequent collaborator, Nadine Marshall. With raw emotive power, random transcended the usual “stagey” limitations of theatre-to-screen adaptations and a Bafta was duly awarded. This led to tucker green’s quietly mesmerising 2014 feature debut, second coming, also starring Marshall as a mysteriously pregnant woman, alongside Idris Elba as her understandably confused husband.

The form of stories always reveals itself in time, says tucker green. “So, second coming was a film. As I was writing it, it was very dialogue-light. It was: image, image, image, vibes.” ear for eye is an apparent exception, since it began as a play, first staged at the Royal Court in 2018, before she adapted her own script for the screen. Yet, says tucker green, the play’s pre-recorded third section was “always written in as a film. So y’know again, [this medium-straddling aspect] is just part of what it is.”

And what is it? Like much of her work, ear for eye is formally innovative and dense with meaning in a way that defies easy summary; you really just have to see it. But we can say it’s a piece about the repercussions of racial injustice in three distinct parts. First: a series of conversations between elders and youngers, revolutionaries and reformers; some American, some British, all Black. Second: a young Black student (played by No Time To Die star Lashana Lynch) challenges her older white professor’s analysis of a mass shooting. The third section consists of white non-actors reading aloud from sections of the British slave codes and Jim Crow laws. The cumulative effect is confrontational and lingering.

For tucker green this is also what distinguishes ear for eye: its sheer staying power. Usually, once the curtain falls on closing night she moves on – “It’s like, ‘See you later!’ D’you know what I mean?” Not this time, though. She points to that spot on the side of her head again. “It’s just trying to be honest with yourself, like what is this thing that’s rattling around in here?”

To answer that question, she called on her producer, Fiona Lamptey, initiating a series of pre-production conversations that mostly took place in late 2019. That timing is significant because ear for eye pre-dates the resurgence of media interest in the struggle for Black lives, precipitated by the May 2020 murder of George Floyd. tucker green is therefore wary of her film being mischaracterised as hashtag-based bandwagon-jumping; a response to “the moment” as opposed to “the movement”. Still, the film poster is rendered in the red, black and green of the Pan-African flag and features the now-familiar BLM graphic of the upheld fist.

Would she describe her work as a kind of activism in itself? She considers this before responding with another question: “How would you describe ‘activism’? I’m not swerving you, but at times it feels like things are getting reduced. The energy around BLM at the moment is good, but the conversation has been there for 400 years … So sometimes it feels a little trite, a little rat-tat-tat, [to say] your film is [activism].”

These issues and others are taken up from various angles in ear for eye, but reverberating throughout is a sense of frustration with the slow pace of progress. As the poster quote has it: “Marchin’ days is over man.” There’s some of that same frustration in tucker green’s voice now, when I ask if she’s noticed any change in the film and TV industry. “For myself, it feels like I’m still hustling the same hustle. You’re fighting to get your shit made, right?”

Black film-makers have had several notable instances of awards recognition and box-office success since second coming’s 2014 release, but, says tucker green, there’s a wider context to consider: “That’s no shade on the Black Panthers, and this and that – that’s great and doing the do – but how many years of ‘It’s Black, it won’t sell’? We’ve said it’s bollocks for I don’t know how long. So now everyone’s like: ‘Oh, hello.’” Her eyebrows shoot up in an expression of pity for the credulous. “You have to ask the gatekeepers. And if they feel that they’re changing, or if they’ve changed in the last couple of years since the lynching of George Floyd, then why then? What? Y’all had to see some shit first?”

Given the way ear for eye’s enacts many current debates around protest and power, I’m surprised by her description of it as “very, very domestic”. As opposed to political? “Well, the domestic can be political, do you know what I mean? The outside world intrudes.” Indeed part of the brilliance of tucker green’s script is how it can sound both conversational and poetic at the same time, with recognisable rhythms from Caribbean-inflected London speech and US hip-hop. These are complex patterns of overlapping, interrupting dialogue, all written out precisely on the page and tucker green is full of admiration for her actors. “Sometimes it’s a bit more stylised [but], even though it’s a little bit on a flow, or a little repetition, it’s still delivered naturally.”

Before tucker green had figured out anything else about her film, she knew this kind of direct character-to-audience communication was essential. To that end, there’s a stripped back, “visually non-literal” set design that’s reminiscent of black box theatre, but distinct from it. “It’s not theatre capture, it’s not shooting a play,” she says. “But it’s all there in what the characters bring to it.” The actors worked out in rehearsals where in the world their characters were situated – “It’s literal in their minds” – but that’s it. “If the audience want to fill in the gaps, the gaps are there to be filled in. Or if you just want to vibes with it, then OK.”

The music, too, is crucial and tucker green worked closely with composer Luke Sutherland to create a score that informs the rhythmic editing, without undermining the dialogue. She explains her preference for lower-case letters as originating in a related creative principle: balancing disparate elements on a single plane. “It’s no biggie, it’s just like, for me, with storytelling, it’s not like, the title, then the person, ‘Debbie’, and then the story. It’s all … on a level.”

Unsurprisingly, given her general aversion to hype and hierarchy, tucker green says she isn’t “personally massively into the language of stars and that”. In recent years, though, some past collaborators have blown up in ways it’s impossible not to notice. What does she think when she sees the likes of Kaluuya, Elba and Lynch scaling ever-greater heights? “I think: ‘I can’t afford you any more!’” she says, then: “Nah, it’s wicked. One: they put the graft in; two: they’ve got serious talent … Like Lashana was in ear for eye, the play and the film, and then in-between she’s doing her little arthouse films, which is all bless,” she says, chuckling at this ironic reference to Lynch’s new role in the ginormous Bond juggernaut.

Indeed, someone else whose involvement spans ear for eye’s stage and screen incarnations is the legendary Bond producer Barbara Broccoli. Coincidence? Or is tucker green, despite her fiercely guarded artistic independence, wielding influence over Hollywood’s hottest casting decisions? tucker green’s eyes glint with mischief. No doubt she could tell me how it all went down, but then she’d have to kill me. So, after a long pause, she deploys some typically gnomic language instead: “I would say, yeah, it feels like there’s some overlap, do you know what I mean? Which is bless in itself.”

• ear for eye premieres at the London film festival, on BBC Two and on iPlayer on 16 October.