The campaign to free Julian Assange takes on intimate dimensions in this documentary portrait of an elderly man’s fight to save his son. Arguably the world’s most famous political prisoner, WikiLeaks founder Julian Assange is a figure pretty much everybody has an opinion about; perhaps more importantly, he serves as the emblem of an international arm wrestle over freedom of journalism, government corruption and unpunished war crimes. For his family members who face the prospect of losing him forever to the abyss of the US justice system, however, this David-and-Goliath struggle is personal – and, with his health declining in a British maximum-security prison and American government prosecutors pulling out all the stops to extradite him, the clock is ticking.

• Documentary