You can’t help but suspect that literary fiction short-changes readers when it comes to portraying black Britons. A novel such as Diana Evans’s Ordinary People, about middle-class midlife marital crises, felt radical mainly because the alternatives tend to be gritty or nothing: a choice between, say, Guy Gunaratne’s In Our Mad and Furious City, about estate kids caught up in riots, or John Lanchester’s south London panorama Capital, without a black British character in sight.

So it’s hard not to hear the double meaning when, at her lowest ebb, Queenie, the titular heroine of Candice Carty-Williams’s smart and breezy comic debut, also set in south London, says “there’s no space” for her. At 25, she’s verging on breakdown, adrift in her job on a newspaper culture supplement, cold-shouldered by her long-term boyfriend, Tom, and unable even to seek comfort at her favourite Caribbean bakery, now a burger joint full of “white kids holding colourful cans of beer”.

Behind it all is the memory of how her mother, brainwashed by a deviously abusive lover, left her living alone at the age of 11. Her break from Tom – really a break-up – stems in part from how she can’t open up to him about the bad dreams that make her thrash out in her sleep. “It’s my stuff!” she says, defensively. “We’ve all got stuff, Queenie,” comes the reply.

One of many excellent things about this novel is how it lets Queenie face that truth without downplaying her own troubles. Chief among the setbacks she encounters along the way is the fallout from sex with an office colleague, Ted, who turns out to be the worst in a veritable shit parade of ill-advised hook-ups, including a cabbie who calls his penis the Destroyer and a junior doctor who is so rough with her that the nurse at an STD clinic asks if she’s being forced into sex work.

Carty-Williams’s handling of that moment shows how supple a writer she is. The nurse’s suspicion reveals what Queenie’s wobbly sense of self-worth has let her in for, but it’s also another example of how she is constantly required to set straight other people’s assumptions. It’s not just “well-meaning white liberals”; when Queenie considers going to therapy, her Jamaican grandmother accuses her of bringing shame on the family, even though, as Queenie points out, she’s the first person in it “to finish school, to go to college, to get a degree, to get a full-time job...” (“Yes! And di firs’ person to go to psychotherapy!”).

While Queenie pins her hopes on decoding a carelessly drunk-texted “X” from Tom, true affirmation comes from the loyal friends in her WhatsApp group: spiky bank clerk Kyazike, literally ready to fight for her former schoolmate, and Darcy, a heart of gold female colleague whose name – a big old wink – lets us know this story about finding yourself, not Mr Right, isn’t a “black Bridget Jones” so much as a 21st-century one.

• Queenie by Candice Carty-Williams is published by Trapeze (£12.99). To order a copy go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £15, online orders only. Phone orders min p&p of £1.99