Finally here after being delayed by the coronavirus lockdown, the film Rocks arrives like a breath of fresh air. A heart-felt celebration of teenage female friendship, this gritty London-set drama about a schoolgirl forced to assume the role of parent to her younger brother when their troubled mother suddenly leaves home is sad, but also joyous, vivacious and hopeful.

Its creation is a collaboration between a Jewish director, Sarah Gavron (Brick Lane, Suffragette), British-Nigerian screenwriter, Theresa Ikoko (with Claire Wilson), and a diverse cast, led by charismatic Hackney-based newcomer Bukky Bakray, as the eponymous teen. This makes the project feel, I suggest to Gavron when we talk on the phone, like a timely rejoinder to the identity politics tearing people apart on social media.

“There is that online but there is also a whole counter thread online of people finding unity,” argues Gavron. “One of the things about this film was that it did bring together lots of people from different cultures, and I think that is the strength of London at its best.”

This was echoed in the “friendship groups” the filmmakers met while doing research in schools. They were “such a mix of cultures,” says Gavron, “and they were finding the similarities and differences, and that was kind of energising their friendship... So, it’s about the connectedness, but it’s also about recognising the difference, that’s so vital to the way we live life.”

“But, God,” she sighs, “you just hope, in this difficult time we’re now in, that we can find unity rather than dissonance, don’t you?”

Rocks, a British-Nigerian like Ikoko, is supported in the film by a diverse group of girls including her British-Somalian best friend, Samaya (Kosar Ali). They all laugh together, dance together, hang out together on a roof top — their friendship a buffer against the isolation hinted at elsewhere — and when the going gets tough, they pull together. The story is like an antidote to London tales about gang violence that ends young lives prematurely. Gavron includes a brief shot of a makeshift memorial on a gate, but it isn’t the story here.

Ikoko grew up on an estate in Hackney, says Gavron, and spoke about an environment “filled with lots of moments of joy” and “amazing friendships” and “a fantastic relationship with her older sister. So we wanted to focus on those elements.”

However, “[Violence] is definitely around them,” she says, referring to her young cast. “And even when we were developing and shooting the film, there were stabbings going on, and the girls knew about them, and they were connected to their communities.”

Something the filmmakers noticed sitting in classrooms, and captured in the film, is that even when “really, really difficult things are happening in their lives, they can find joy, moment to moment, in a joke, or in something good happening at school. So they move between these different worlds quite rapidly.”

Hearing this, I imagine how difficult it must have been during the school closures. Gavron, who is 50 and married with two children, remembers how important female friendship was as a teenager. “It’s everything at that age,” she says. “Your friends are your family, and they’re the source of joy and support as well as difficulties, but they really, really are a strengthening bond at that point.”

She admits that she was the furthest away from “the lives and worlds” of the young women in Rocks, and “had the most to learn”. On the other hand, she began her career as a documentary maker, and has always had a penchant for exploring other people’s environments. I’d read that her maternal German-Jewish grandmother had fled here alone, and ask whether having that immigrant experience in her background inspired her to look at other communities.

“Definitely,” Gavron exclaims. “Undoubtedly that just sort of imprinted itself on me. She died in my late 20s and her story made this massive impression on me.

“She left Germany when she was 17 as an unaccompanied minor. She didn’t come on the Kinderstransport, she didn’t have support networks, so she had to fend for herself and had a very difficult time. She tried to disguise the fact that she was Jewish and the fact that she was German, because she was afraid. She really lost her whole childhood in that moment, never to regain it, and had to become prematurely adult. Which is also what happens to Rocks: she has to become adultised before her time.”

Coming from immigrant grandparents or parents is “enriching”, suggests Gavron, “but it also gives you a different view on the world, a slight outsider perspective.” Recently, her Jewish Danish husband, the cinematographer David Katznelson, whose father was in Theresienstadt, told his family’s story. “So I often think about those experiences and the outsider experience,” she says.

Through Katznelson, Gavron has also got more in touch with Judaism. Her upbringing was “very secular”, not least because her mother, Nicky Gavron, a former deputy mayor of London, “was brought up sort of hiding it, because her mother had such a difficult time.” Her father, Robert, “had more of a traditional upbringing,” she says, “but he was really a secular Jew. So, I was surrounded by people who were doing the traditions, but we weren’t at home.” Her in-laws “do a lot more,” she laughs, “so I’ve sort of caught up a bit, which has been a learning experience.”

If there is a theme running through her work, it is the desire to tell stories about people who aren’t necessarily marginalised in society, but are “margnalised on our screens”. “You have to see it to be it,” she says, explaining that, as a woman, she didn’t realise she could be a filmmaker until her late teens/early 20s, and saw films directed by the likes of Sally Potter, Mira Nair, Jane Campion. Many of the young people the filmmakers met while making Rocks also felt culturally under-represented.

“One of the important things for them... was that girls like them growing up would feel that they were seen. That they were acknowledged on their screens and their stories are important.”

Given this, I ask if events since the original release date mean that aspects have taken on a different or greater significance for her.

“Yeah,” says Gavron. “There’s been Black Lives Matter, and a sort of focus on young people, and I think it feels more important than ever. I’m not really speaking for me, but speaking for the team, these young women . . . [It’s time] that we focus on them.”