Beauty is in the eye of the beholder but when that beauty defies the social mores of a prejudiced era, it must be cherished in secret.

Belle is the enchanting dramatisation of a true story of fortitude across racial and class divides at a time when pompous men of privilege were vociferously debating the end of slavery in England.

The high-profile case at the centre of the debate concerned the crew of a ship called the Zong, who had thrown dozens of slaves overboard because they claimed they did not have enough supplies for the duration of the voyage.

When the ship reached port, the Zong's Liverpool-based owners demanded compensation for the lost slaves but insurers refused to honour the claim.

The subsequent trial posed uncomfortable questions about the monetary value of human life.

Inspired by an 18th-century painting commissioned by William Murray, who was then Lord Chief Justice of England and Wales, Amma Asante's handsome period piece illuminates the debate and some of the characters, whose lives intersected at this historical crossroads.

Captain Sir John Lindsay (Matthew Goode) brings his illegitimate, mixed race daughter Dido (Lauren Julien-Box) to England and entrusts the child to his aristocratic uncle, Lord Mansfield (Tom Wilkinson) while he returns to sea.

Lord Mansfield's wife (Emily Watson) is opposed to the plan but he permits Dido to stay, allowing his great-niece to become a constant companion to her cousin, Elizabeth (Cara Jenkins).

The girls blossom and Lady Elizabeth (now played by Sarah Gadon) prepares to seek a wealthy husband.

"Elizabeth must secure her bread and butter," Lord Mansfield reminds his wife.

Dido (now played by Gugu Mbatha-Raw) is afforded certain privileges by her lineage but she must remain behind closed doors at important social gatherings.

Oliver Ashford (James Norton), the handsome offspring of Lord and Lady Ashford (Alex Jennings, Miranda Richardson) is a potential love match for Elizabeth but he is more interested in Dido.

However, Dido's head is turned by idealistic lawyer John Davinier (Sam Reid), who is heavily involved in the Zong case and opens her eyes to the barbarism of slavery.

Elegantly scripted by Misan Sagay, Belle is a beautifully crafted companion piece to 12 Years A Slave that traverses a moral maze through British eyes and reminds us that we have blood on our hands too.

The ensemble cast delivers excellent performances, particularly Mbatha-Raw, who possesses beauty and vulnerability on camera.

She catalyses smouldering screen chemistry with Reid, and Wilkinson brings pomp and circumstance to his pivotal role as a man with the power to chip away at the foundations of the legal firmament.

Dramatic momentum steadily builds to Lord Mansfield's deliberation on the Zong case, watched intently by Dido and Davinier.

Like them, we're spellbound by his ruling.