Even if writer-director Rungano Nyoni's film were a lesser achievement - less unsettlingly complicated, less bitterly funny, less bluntly sad - it would still have the witch truck, one of the great cinematic images of this or any other year.

Nyoni, working in English and the local language of Nyanja, has an unforced way of dealing with themes like exploitation, oppression and superstition, showing how easy it can be for nonsense to pass itself off as sense.

Nyoni is clearly confident in her vision and the story she wants to tell, and in her capable hands, the result is spellbinding.