On Black Sisters' Street, By Chika Unigwe

Not many novelists would wander around the seedy red-light district of Antwerp in a mini-skirt and thigh-high boots to carry out research. But this is what Nigerian writer Chika Unigwe did for her novel about the lives of African sex workers in the Belgian city. She also spent time persuading these women to share their stories.

Her diligence has paid off. On Black Sisters' Street is a probing and unsettling exploration of the many factors that lead African women into prostitution in Europe, and it pulls no punches about the sordid nature of the job. Four naive young women, Sisi, Joyce, Ama and Efe, fall under the money-making spell of pimp-daddy "Senghor Dele" in Lagos.

Rich, vulgar, ruthless, he specialises in exporting girls to work in Belgium for a modest fee of 30,000 euros. This they must pay back in monthly instalments over many years of turning tricks ten hours a day. They don't all know that this is what lies in store but, fake passports withheld, the consequences for those who try to escape are dire.

Sisi, around whom most of the novel's suspense revolves, is an ambitious graduate unable to find suitable work. Efe is a teenage mother struggling to raise her son with no support from his father. Ama has escaped an abusive childhood only to find her dream of escaping Nigeria crushed by a dead-end job. Joyce, without family, home or money, is abandoned by her boyfriend. The women's dreams come in different sizes, from financial support for struggling relatives back home to the allure of big houses, fancy cars, gold jewellery and expensive plait extensions.

Unigwe's vigorous prose is at its best when describing the utter humiliation Sisi feels when forced to dress like a hooker in "a gold-coloured nylon skirt" that rode up her legs when she walked and "showed her butt cheeks when she bent". So too with the degradation of her first encounter with a client in a toilet: "She baptised herself into it with tears, hot and livid, down her cheeks, salty in her mouth, feeling intense pain wherever he touched, like he was searing her with a razor blade that had just come off a fire".

Men in this novel are generally drunks, murderers, rapists, weak, cold-hearted, pathetic - although Unigwe avoids the fallacy of women as passive victims. Hers make choices, for which there are consequences. But their choices are restricted by circumstance and the Lagos they leave behind is a harsh place to survive, where "on any given day one was likely to find a corpse abandoned by the roadside".

She shows what the women become, too. Sisi, who felt she was living the dream on her first day in Belgium because she was eating jam, can "no longer bear to look at herself", while Efe's plan is to run her own brothel one day when she has paid of her debt. What Unigwe does brilliantly is to delve into the psychology of each woman, eliciting different levels of empathy.

This is an important and accomplished novel that leaves a strong aftertaste. Unigwe gives voice to those who are voiceless, fleshes out the stories of those who offer themselves as meat for sale, and bestows dignity on those who are stripped off it.

Bernardine Evaristo's 'Blonde Roots' is published by Penguin