Alex Garland (writer of 28 Days Later, Sunshine, and Dredd and writer/director of Ex Machina, Annihilation, and the unsettling Men) has lately been threatening that Civil War will be his last film in the director’s chair. If true, it’s a breathtaking final sucker-punch of a film, a movie torn from tomorrow’s potential headlines as it depicts, with a ruthless nihilism, the disintegration of American society and its collapse into chaos and anarchy.

Civil War follows the travels of four determined photojournalists across a battle-torn America, desperate to make their way to Washington DC and an audience with the President (a cameo from Nick Offerman) before the rebel factions (including the combined might of Texas and California) launch their final advance on July 4th. They’re a tightly-knit, well-drawn bunch, from Kirsten Dunst’s weary veteran photographer Lee, Wagner Maura as Joel, Lee’s old colleague, Stephen McKinley Henderson as Joel’s older mentor Sammy, and Cailee Spaenay as Jessie, a 22-year-old young photographer keen to make a name for herself as a warzone photojournalist. But there’s danger everywhere, from snipers lurking on the rooftops of small towns trying to avoid the conflict to a bunch of terrifying nationalist-militia soldiers led by an uncredited Jesse Plemons. It’s here that an already dark film turns into something much darker and where our characters realise not just what’s at stake but also how close they are to violent death every second of every day. Rendezvousing with a military convoy at Charlottesville, they join the great push on to the capital and finally the White House itself…

Civil War is not for the faint of heart and not for those of a depressive nature. It’s tough, callous, and unforgiving, brilliantly realised but utterly without light or shade., It offers little of a redemptive nature for its characters, the situation they find themselves in or, indeed, the world. Garland keeps his story’s geopolitical machinations purposefully vague – America is at war with itself, and that’s all we need to know. It’s a brutal, bruising, emotionally exhausting film that you’re not likely to consider revisiting again and again.  It is, though, a shocking and powerful piece of work that needs to be seen – to be endured – as a potent reminder of the savage ruthlessness of war and the unnerving fragility of a state of social order that we tend to take for granted.