The Prisoner of Paradise, By Romesh Gunesekera

It is 1825. Lucy Gladwell, a callow young Englishwoman, arrives in Mauritius to live with her aunt and uncle in a grand plantation house. She is, of course, ardent and plucky, idealistic and hopeful that here, away from stuffy England, she will be emancipated, find her true self and an all-consuming love.

The island has been under the Dutch and French, and is now claimed by the British. Its inhabitants are postcards of a long history of migrations, conquests and colonial exploitation, mixing and merging of blood and shifting allegiances. Pesky abolitionists are determined to stop the use of black slaves, so a fresh supply of hapless humans - convicts, serfs and bondsmen - are shipped from India. Race divides the de-humanised and class segregates the Indian "coolies" from profiteering south Asian entrepreneurs and adventurers, who rub along with European masters and mistresses. Uncle George is a harsh official; his kindlier wife, Betty, buys plants, throws parties, maintains domestic order and Victorian conventions.

Mauritius, like Zanzibar, is an evocative isle, dreamlike and nightmarish. I often went to Zanzibar as a child, a place of serial subjugation and occupation, beautiful and damned. Though she tries to deny her feelings, Lucy is irresistibly drawn to Don, a proud and handsome Ceylonese translator who works for an exiled prince. On this hot and heady island, controlled by unbending rules, will it be a dangerous liaison, a fatal attraction?

The film is waiting to be made. It's all there: an inverted but murky Pride and Prejudice, paradise spoilt, ill-fated lovers, rascals, imperial wickedness, the cunning of natives, plots and mêlées and a host of fabulous flowers. Romesh Gunesekera's novel takes the bouquet of romantic clichés and throws it up, makes it soar and scatter, leaving its scent in the air.

Though we've met the characters often enough and the story is familiar, anxiety and uncertainty build up: a sense that the unexpected will catch us out. And it does, often. Exquisite prose awakens all the senses: "The birdsong next morning laced the sky in a tapestry of sound... cocoroos punctuated by coos and tweets; a chorus of pips and purls and curls and caws... The sun reached deep below her skin like the tongue of an inner flame." When a hurricane hits, "a river burst out of the sky. Daylight was doused... he saw a huge tamarind out on the road being pulled by the wind: the leaves and branches turned inside out as if in shock". The eroticism of nature and its menaces are ever-present; light and shade, wisdom and foolishness, inanity and brutality, pleasures and pain. Like Lucy, we are on an island we will never understand.

The perversions and protocols of racial domination appear changeless and given. Rebels have to be broken, forced to accept the status quo. After an attempted insurgency by Indian labourers, one is mutilated, killed and hung up. Uncle George is unabashed: "Swift action has a purgative effect that is both necessary and desirable. Justice demands it. If a man attacks the norms of our society, then he needs to be removed from it forthwith".

These men have whips and guns and gallows yet can't stop the chaos of their inner lives. Nor can colonial memsahibs who maintain well-appointed gardens and the niceties of social life. The membrane of desperate pretence bursts and mayhem ensues. Lucy, with all those unsuitable longings, has no chance. She is no operatic, tragic heroine, but her innocence moves and raises protective instincts in the reader.

My biggest criticism of the book is that the oppressed individuals are bit players, barely delineated, in effect dehumanised further by authorial indifference. Also, there are too many unnecessary characters. And some of the dialogue reads like a bad parody of Jane Austen. Here is Aunt Betty on embroidery: "I would recommend engagement with the damask... if done with true feelings... it will divert the distress that may otherwise consume us". Finally, the author sometimes gets carried away and overwrites. Gunesekera could, but hasn't quite managed to, write an epic on imperialism. The novel, though, is a terrific read: pacey, political, moral, atmospheric and, yes, definitely romantic.

Yasmin Alibhai-Brown's 'The Settler's Cookbook' is published by Portobello