Capital in the Twenty-First Century is not so much a critique of capitalism as a critique of its corruption. In New Zealand film-maker Justin Pemberton’s documentary, French economist Thomas Piketty’s sweeping 700-page book from 2013 is condensed into an illustrated lecture that runs under two hours. Piketty appears as a talking head, bolstered by a cast of lively academics and economists who analyse more than 300 years of social, political and economic change, showing how unchecked capitalism works to widen the gap between rich and poor.

That might seem obvious, but Pemberton and Piketty encourage viewers to think about the way the acquisition of capital has been packaged and sold to the middle classes as a social leveller destined to improve the quality of life for all. Not so when today the 1% that hold 70% of the world’s wealth remain a stark reminder of Britain’s 18th-century aristocrats, whose inherited land and wealth set them apart from the general public whose average life expectancy was just 17. It’s brisk, first-rate stuff, and not especially radical. I can see it being shown in schools.

Documentaries should be more than a vehicle for information. Here, the message is hard to argue with, but the medium – an excess of music video-style cutting, contemporary pop culture montages and literal music cues – does the material no favours.