1965, UK, directed by Peter Watkins
Director Peter Watkins's best-known and most controversial work, The War Game is a pseudo-documentary that re-creates the aftermath of a Soviet nuclear attack on Britain, with the film taking the format of a television news program, complete with an authoritative BBC voiceover and a list of source materials at the film's conclusion. Although commissioned by the BBC, the project was effectively censored by the Corporation for almost twenty years, even though theatrical screenings took place (including in the US, which helped Watkins gain enough exposure to make his later Punishment Park in that country, and also netted the film an Oscar).
The depiction of a society which collapses absolutely, in both physical and moral terms, in the wake of the attack is utterly devastating, and the sense of civic disruption is achieved through the use of tellingly local details (the sight of the usually unarmed British police force brandishing guns is especially chilling, while there's something oddly unsettling in the simple fact that the men in uniforms have neither the time nor the resources to shave). Watkins is interested in the consequences of the attack at ground level rather than grand strategy, and it's this sense of individual suffering that's often unbearable; he is also blunt about the racial and social prejudices raised by mass evacuations (just a few years before Enoch Powell's notorious "rivers of blood" speech on immigration). In creating his depiction of a post-nuclear collapse, he draws heavily on the experiences of Hiroshima/Nagasaki but also on the firebombings of Dresden and other German cities, and it's likely that his unapologetic critique of such wartime actions was as provocative to the government of the day as his depiction of nuclear horrors; Winston Churchill, who oversaw Dresden and other bombing campaigns, died in early 1965, and his legacy was not lightly called into question.