It is not until the acknowledgements at the end of his Man Booker-longlisted 21st novel that the South African author André Brink reveals the historical roots from which it sprang: "[The slave woman Philida] worked as a knitting girl on the farm from 1824 to 1832," he writes. "The discovery that her master Cornelis Brink was a brother of one of my own direct ancestors, and that he sold her at auction after his son Francois Gerhard Jacob Brink had made four children with her, triggered this novel."

It is a startling admission from a hero of the anti-apartheid movement, made in an era in which everyone seems to be apologising for slavery. Instead of an apology, Brink pieces together a story from the fragments of information that he can find about Philida. Such as that, "in her deposition, Philida alleges that she and Frans have 'made' four children. But in the Slave Rolls and other official sources only three children are ever listed …"

The novel opens in 1832, with the coming liberation of slaves a thrilling rumour around the longhouses and farms of the Cape. Philida is walking with a baby on her back to the office of the Slave Protector, to make a complaint about Frans, the son of her owner. The complaint is not about what he did to her, for eight years, in the bamboo copse beyond the vineyard, but "because he take me and he promise me things and now he is going away from me … He say he will give me my freedom."

Philida's nerve in doing this – and in the way she speaks to the bony white man – is almost too strange for fiction. And yet, her visit to the Slave Protector is a matter of record. Based on the evidence, the Philida that Brink paints is credible, and wonderful. The Protector's verdict, however, will not come as a surprise, and nor will the stories – all true – of hangings, flayings, forced labour and rape. Against this background, Brink's fictional explanation for what happened to Philida's first child rings all too true.

Perhaps the most surprising thing about this novel is that its overwhelming sense, somehow, is one of hope. Philida never does get to write her children's names in the family Bible, but, nearly 200 years later, Brink does rather better than say sorry for what his ancestors did.