★★★★☆

CONTROVERSIAL Chinese artist and activist Ai Weiwei brings us a sobering, harrowing and utterly essential look at the global refugee crisis and the devastating effects it’s having not just for the people forced to leave their homes but the rippling effect it has on humanity as a whole.

Ai manages to achieve a sense of both epic scale and startling intimacy, putting the crisis in frightening worldwide context as he documents the issue in 23 countries (everywhere from Turkey and Germany to Afghanistan and Mexico) with the help of hundreds of crew members. This compelling combination really drives home his points about the urgent tragedy of a situation that literally affects tens of millions of people at this very moment.

There’s no sense of self-absorption or cheap provocation going on here; Ai himself doesn’t intrude on the film, appearing only sporadically as a kind of observer right alongside us as horrified onlookers, using the documentary format to speak in plain, startling images that holds your attention and doesn’t let go for a second of its substantial 140 minute runtime. This is an artist using his eminently inventive eye to paint a vital, catch-all portrait of what should continuously be a forefront topic.

Shocking on-screen headlines and statistics – “refugees on average spend 26 years displaced from their true homes” – go hand in hand with impressively epic drone-shot bird’s eye views of makeshift camps, uncomfortably up-close-and-personal interviews (many of them with subjects facing away from us out of shame) and enveloping journeys following the titular human flow of people fleeing war, persecution, climate change and famine. Ai’s approach marks it out as a distinctly cinematic documentary.

The overtly political ramifications is definitely touched on throughout, not least in its explorations of how various nations embrace or shun the acceptance of refugees, namely the variously rigorous border controls or in his interview with Jordanian Princess and Unesco Goodwill Ambassador Dana Firas.

But it’s primarily a film about empathy and the endeavour to put a vital human face on the refugee crisis, to understand that these are real men, women and children with individual hopes and dreams of a better life suffering through what to most of us would be an unimaginable existence.

“Being a refugee is much more than a political status. It is the most pervasive kind of cruelty that can be exercised against a human being. You are forcibly robbing this human being of all aspects that would make human life not just tolerable but meaningful.” Ai’s film doesn’t arrive at any easy answers, inevitably because none exists, but engages with the issue in a potently human and unsanitised fashion, resulting in one of the most important and unforgettable films of the year.