Protest documentaries on still-burning topics often risk seeming like public service announcements. Not this short, pointed and entirely engrossing doc from New York-based Madeleine Sackler, which views the injustices of Belarus’s dictatorship through the keen eyes of a local underground theatre troupe. The Belarus Free Theatre – multiple connotations of ‘free’ apply, some bitterly ironic – was already subject to government scrutiny and frequent raids prior to the farcical 2010 election. (Despotic president Alexander Lukashenko claimed a landslide victory and had opposition candidates imprisoned). Amid the ensuing furore, the BFT’s eight members skipped the country to escape arrest, taking their act and their message to Manhattan and, later, the Edinburgh Festival. But this exile couldn’t last for all of them. How the troupe has remained united against practical and political odds makes for rousing, urgent viewing, with Sackler balancing intense performance footage with the actors’ personal dramas. In one scene, some of them take their cause to the streets of London, attempting to bend the ears of harried passers-by. They should have our attention now.