A United Kingdom.

That’s the name of director Amma Asante’s latest film that opened last month’s London film festival.

It’s also the one thing this country ain’t right now.

Based on the true story of the future king and leader of Bechuana land – since rechristened Botswana – A United Kingdom is a trip back in time to a less evolved and civilised age in British history.

So, you’d imagine it’d be very popular with those swivel eyed lunatics and closet racists who want us to leave Europe.

Just don’t mention that a black man is the hero of this particular story.

Better not mention the white woman he takes as his wife either.

Being too young to know any better, I had no idea who Seretse Khama was before seeing this film, or the role our government played in trying to obstruct another nation’s rightful heir from leading their people.

But while the story changes, the song remains the same.

Like every other empire throughout history, our past is a largely shameful one – and there’s nowt more shameful than the South African policy of apartheid that forms the political backdrop against which Khama struggles for justice.

David Oyelowo is great as Khama, and he’s even greater in person as I found out during a festival press conference.

A United Kingdom simply wouldn’t have been made without Oyelowo’s efforts; not only does he take on the lead role, but he helped produce the film and was also instrumental in getting Asante on board as director.

I imagine he might have had a part to play in the casting of his wife too.

Rosamund Pike plays Ruth Williams, the woman who would be Khama’s wife, and Jack Davenport leads the supporting cast in providing a little levity to the serious issues this film raises.

Yet, despite the great efforts that have gone into making A United Kingdom, it’s a worthy film rather than a great one.

The film struggles to live up to the remarkable true events it is based upon and, as ever with these historic tales, it’s hard to escape feeling that a documentary wouldn’t have been a better fit for the source material.

But sometimes it’s more important to shine a light on a past that should not be forgotten than create a two-hour cinematic distraction designed to make a lot of rich studio men even richer.

Hell, that’s always more important.

Jonathan Campbell