~Please do not ask how much of it is true. Glory in its sumptuousness. Gorgeous costumes and even more gorgeous interiors. Most of them are genuine Robert Adam, though not the Adam interiors at Kenwood House where much of it is set but was not filmed. There are two story lines. First, there is the political/legal one concerning the real case of The Zong, where the ship owners sought to collect on the insurance on slaves who were thrown overboard when water ran short.

Second, there is the personal story of trying to marry off the two nieces. The latter is Jane Austen territory, the former is Frank Capra territory, with Mansfield cast in the role of the curmudgeonly old man who is persuaded to do the right thing in the end, complete with a “whatever happened to the radical young man I married?” scene with Lady Mansfield (Emily Watson), and lines like “what is right can never be impossible”.

Inevitably the two stories intersect, proving that you can do the right thing and marry the right man. The film bestows a fortune on Dido together with an irony: she cannot marry someone below the rank of the Mansfields but no one of the rank of the Mansfields will marry her because of her colour (her illegitimacy is oddly only mentioned once). She cannot be presented to society like her beautiful, blonde cousin who (further irony) has no fortune and hence fails to snare the man she wants. Nevertheless, stay-at-home Dido attracts two extremely attractive suitors.

She has to choose between the handsome James Norton as Oliver Ashford, penniless but aristocratic, and the (if possible) even handsomer Sam Reid as John Davinier, penniless but middle class and idealistic. There is of course no contest. James Norton fit neatly into the upper class, manly young man roles right out of drama school, first as a badly behaved rich Oxford undergraduate in Posh, and then as a brilliant Captain Stanhope in Journey’s End.

 More recently he took a “toff-break” on TV by playing the terrifying pathological criminal in Happy Valley. In Belle he positively oozes charm. He sees Belle as “exotic” and therefore likely to be a lot of fun but here he is going to be disappointed. Gugu Mbatha-Raw, who has portrayed Cleopatra, plays Dido as high-minded, dignified, and committed. Rather than wait 200 years for someone to invent disclosure rules, she steals documents from Lord Mansfield and gives them to her pamphleteering boyfriend, thus inventing “leaking to the media”. She could be better informed. “Is she a slave?” she asks of the black servant in the London town house. She could not, since slavery had years before been declared unlawful in England thanks to—Lord Mansfield, who fails to cite Somersett’s Case over the breakfast table.

Attractive though he is, Oliver Ashford would bring with him the in-laws from hell. His elder brother, played by “Draco Malfoy’” (actor Tom Felton) is a snobbish, bigoted bully. He commits both the sexual assault and the discrimination theme of which we have been warned. He spurns cousin Elizabeth who does not understand what a lucky escape she has had.

His mother is a monster. The role of Lady Ashford was clearly required to liven up the film which so far had relied upon the emotional power of Penelope Wilton as lovelorn Aunt Mary. Lady Ashford needs, say, a Miranda Richardson under strict orders to take no prisoners and luckily she is played by Miranda Richardson who is glorious and takes no prisoners.

Alex Jennings, as Lord Ashford, knows better than to appear (let alone compete) in the same scene with her. As idealistic John Davinier, Sam Reid seems uncomfortable. He will be in The Riot Club, the film of Posh and time will tell if he is happier downing Bollingers and smashing up the place with the empties.

Mansfield dismissed him from being a pupil in his “chambers”, but he is forgiven in the end. In the last scene, superbly shot in Middle Temple Hall, Mansfield gives the “right” judgment in The Zong which seems to have kick-started “every case turns on its own facts”.

He offers to sponsor Davinier’s membership in “the Inns of Court”. I like a film where it is the barrister who gets the girl.