A young girl is transplanted from poverty into the opulence of an English country house, in which she will always feel an outsider. The girl, now a young woman, has to choose between suitors: an eligible bachelor from a family with dark secrets and darker passions, or the man whom she truly desires, but who is from an unsuitable background. Later, she is threatened by inappropriate behaviour in a pleasure garden. Eighteenth-century politeness masks violence, disorderliness and crime. The legitimacy of this society is put on trial in a spectacular legal trial.

Amma Asante’s historical romantic fantasy Belle has clearly done its homework: the script by Misan Sagay gestures towards a range of eighteenth-century materials to build a convincing filmic world. Echoes, surely deliberate, of Jane Austen’s Mansfield Park, Frances Burney’s Evelina, even William Godwin’s Caleb Williams, help to create a self-consciously literary screenplay. Asante and Sagay use the true story of Dido Elizabeth Belle, a mixed race girl adopted into her uncle Lord Mansfield’s household, to give these literary allusions a significant twist: because of her parentage, Dido is much more of an outsider with the Mansfields than Fanny is at Mansfield Park. It is Dido who runs away from one suitor to seduce another in the pleasure gardens – much less conscious of her reputation than Burney’s Evelina. The corrupt chivalry of a Falkland is not the subject of the trial at the heart of Belle; instead, the ethics of the British slave trade, and the morality of the political and economic empire which it underpinned, are challenged.

Gugu Mbatha-Raw is excellent in the title role, by turns naïve, alienated, incisive and angry. She combines these emotions in a throwaway scene at breakfast when she asks about the status of one of the Mansfields’ black servants. Her question, ‘is she a slave?’, uncomfortably breaches the reigning decorum, and the indignant negative she receives in reply fails to resolve the issues around her own status – she is neither a servant nor wholly part of the family, disallowed from dining with either in company.

Mbatha-Raw is ably supported by a cast of superb older actors, including Penelope Wilton, Emily Watson, Miranda Richardson (relishing her role as a hypocritical, racist snob), and Tom Wilkinson, playing Lord Mansfield as an Establishment man torn by conscience. A small scene between Mbatha-Raw and Wilkinson stood out for me as an eighteenth-centuryist. Lord Mansfield finds Belle reading Thomas Day. He asks her whether she identifies with Day’s sympathetic treatment of African characters. She replies that she feels at home nowhere. This little scene combines deft (perhaps anachronistic) literary allusion with complex characterisation, challenging its audience with sophisticated questions about race, gender and identity.

Belle has received mixed reviews, with criticisms levelled at its cumbersome exposition of the legal case surrounding the Zong slave ship, its uneven mix of period drama and social critique, and the chemistry between its lead actors. For me, the film uses its period setting to reflect upon complex, unresolved issues about belonging – to a race, a gender, a class, a country; that the film does not manage to resolve them is a testament to their complexity rather than imaginative or creative failure. The film does magic up a happy ending for Belle and a leading role for her in the Mansfield judgment on the Zong case; however, Belle’s active involvement in the outcome of the trial – stealing documents and sparring with Mansfield – echoes similar liberties taken in adaptations of Mansfield Park, making Fanny more active and less passive-aggressive, for example, and her partially invented romance with the idealistic lawyer Davinier fulfils Hollywood’s genre expectations, seeing the film kowtow to conventions it critiques elsewhere.

Belle, directed by Amma Asante, was released in the UK in June 2014.