It's quite a while since I have seen a film with such a devastating impact as Sam Mendes's superb, adrenaline-rush of a movie as I (now on general release). April 1917 and the First World War is still raging and costing the lives of thousands of British troops. We open, though, in a tranquil field in which napping Lance Corporal Blake (Dean-Charles Chapman) and Schofield (George MacKay) are awakened and sent to report to their commanding officer (Colin Firth) who has a perilous mission for them. A massive mobilisation of British troops, including Blake's brother, are unknowingly heading into a German trap. With telephone lines down, it's up to the two young soldiers to traverse dangerous ground and physically deliver the order to stop the battle from happening and in the process save the lives of 1,600 men. And then they're off, through a post-apocalyptic landscape of barbed-wire, broken tree stumps, mud lakes left by shell craters, dead bodies, rats, bombed-out towns and elaborate tunnels. But the men must carry on and the film conveys, along with these men's sense of futility and fear, the strange nausea and exhilaration that Blake and Schofield feel, the nihilistic elation that comes with the moment-by-moment experience of survival, fiercely holding onto life with every eardrum-splitting sniper shot. Ahead of them, though, lies chaos and loss. The most extraordinary sequence comes when a German airman crash lands almost on top of Blake and Schofield and there is a moment of simple human compassion when the German staggers out of his blazing craft, dying and begging for water. Schofield runs to get him some from a rusty pump and behind his back - behind the audience's backs - the story's most fateful event occurs, off camera. It's a staggeringly bold bit of storytelling and it comes off. This is a wildly audacious reinvention of its genre and Mendes's first screenplay co-written with Krysty Wilson-Cairns. It is inspired by conversations the filmmaker had with his grandfather, Alfred H Mendes, who fought at the Somme and augmented by meticulous research undertaken at the London Imperial War Museum. Shot on a single camera by master cinematographer Roger Deakins, Mendes attempts the almost impossible, two hours of a sprawling soldier's quest, all done using a continuous fluid tracking shot, meaning there is not a single visible cut, and giving the urgency and intensity of a nail-biting thriller. Beautifully played by MacKay and Chapman, our two heroes couldn't be more different. Blake is a cheeky chappie, good with maps and good for laughs; Schofield is more reserved, constantly masking his feelings. Both actors gain our trust and empathy and create an intimacy and immediacy that make you live every step with them. This stunning movie is without doubt Mendes's best film yet and a true testament to the men who fought in trenches and muddy fields between 1914 and 1918, a robust, mesmerising hymn to a generation who made the ultimate sacrifice for something much bigger than themselves. https://www.youtube.com/watch?vgZjQROMAh_s 1917 is showing in cinemas nationwide.