When Seretse Khama and Ruth Williams fell in love in 1947, their relationship was already made difficult by dint of being interracial: Khama was from Bechuanaland (now Botswana), and met Williams in London while studying to be a barrister. But the fact that Khama was also heir to the throne of Bechuanaland complicated things even more.

When the couple got married, it put a lot of prejudiced noses out of joint, particularly ones in the government of neighbouring South Africa: a happy interracial marriage just north of the border would have made a mockery of apartheid. South Africa put pressure on Britain (of which Bechuanaland was protectorate) to intervene, and the Labour government conspired to have Khama exiled from the country he was supposed to be ruling.

Seretse eventually became Bechuanaland’s president. It’s a genuinely inspiring story, turned into a historical pantomime by director Amma Asante. Its heroes are played with enthusiasm by David Oyelowo and Rosamund Pike, but due reverence doesn’t make for compelling characterisation, and its villains are completely fictional people drafted in to personify the real-life governmental malfeasance. Jack Davenport does dastardly things like raise his eyebrow and offer Khama a glass of sherry; Felton sports a hat, moustache, and glasses, presumably so that no one recognises him as Draco Malfoy. They are there to be splutteringly outraged when bested.

Other characters are even less convincing. One actually announces himself as ‘just a burnt-out reporter looking for a story’, and then says nothing for the rest of the film despite having an important part to play. The actors struggle to get their tongues around stiff sentences that sound less 1950s than Regency era. Faced with such dialogue, Terry Phato (playing Seretsi’s sister Naledi) should feel relieved that she hasn't been given much to say.

A United Kingdom isn’t unlikeable – it’s just not very good. But then true stories are often dully told on screen. Directors seem to think that that the words ‘inspired by actual events’ can substitute for dramatic intrigue or three-dimensional characters, when actually an incredible true story needs extra skill and effort in order to be made credible.

If you want an amazing story loosely dramatized with clichés, then go see A United Kingdom: it’s quicker than reading the book (Colour Bar by Susan Williams). But if you want cinema – if you want style, character, and ambiguity – we recommend you watch Jackie.