Novelists are irresistibly drawn to the “what if?” game, imagining a world in which Marilyn Monroe survived or Hitler won the Second World War. But it has seldom been done on the scale of Bernardine Evaristo's astonishing new novel, which takes one of the great horrors of history and turns it on its head.

Blonde Roots is the story of a young girl, captured by slave traders and transported to a life of barely credible savagery in the New World. Slavery has been documented in minute detail and the floggings, rapes and amputations suffered by runaways are well known. But Doris is blonde and English, her new masters black and African, and 400 years of history are presented in a new and disconcerting guise.

Doris Scagglethorpe lives in the North of England, where life is hard - her parents and sisters are little more than serfs, their lives ruled by the local squire - but filled with love and affectionate sibling rivalry. Then she is seized, taken to a slave market and thrown on to a ship, where she lies on a shelf in the stinking hold and learns the reality of a slave's existence.

When the novel opens Doris, renamed Omorenomwara by her masters, is about to run away. On the terrifying journey to freedom, expecting to be recaptured at any moment, she remembers her life before she was enslaved - the plain English food, the games with her sisters, the way her mother coped with her father's heavy drinking.

It isn't an idealised existence, but the contrast with Omo's daily experience as the house slave of Chief Kaga Konata Katamba I, also known as Bwana, is endlessly painful. At first she is assigned to be the playmate of Little Miracle, the spoilt daughter of the household. “You have betrayed me, Omo, and I am, like, totally devastated”, she wails when Omo dares to express the truth about their “friendship”.

Evaristo is a poet and the novel is full of playful anachronisms, many of them based around language and emotions that sound decidedly 20th century. But it's also a satire, almost Swiftian in its imaginative leaps, in which humour and suffering are effortlessly intermingled. Omo's early experiences as a house slave do not even begin to prepare her for work in the fields, where her pale skin is seared by the pitiless sun. Bwana is a pamphleteer, author of The Flame, a publication that boasts about his humble origins and produces spurious racial arguments for slavery. Europeans have stunted brains, he declares, and are incapable of feeling pain in the same way as Africans: “Beating the hide of a Caucasoi is more akin to beating the hide of a camel to make it go faster”.

The inhuman treatment of the white slaves in Blonde Roots is the practical application of this ideology. Some people may be offended by Evaristo's precise inversion of the relationship between slaves and owners, which requires her to invest Africans with the worst characteristics of 18th-century Europeans. But she is making an important point about the way in which an excess of power corrupts and distorts human nature. This brilliant novel will fulfil her purpose of making readers view the transatlantic slave trade with fresh eyes.

Blonde Roots by Bernardine Evaristo
Hamish Hamilton £16.99 Buy the book here

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