After it won an Oscar for Documentary Feature, the Academy of Motion Picture Arts and Sciences changed the eligibility rules for the category.

Despite being produced by the British Broadcasting Corporation (BBC), the film was banned from television. The official reason was violence and depiction of human suffering, but others hinted that the real reason was because it went against the official government line concerning the survivability of a nuclear attack. The ban didn't forbid cinematic distribution, so the film had a wide theatrical release and won four major film awards.

Although this film is not a documentary, it won the Oscar for Best Documentary Feature, the only fictional film to win this award.

The extras for the film were from the towns of Gravesend, Dartford and surrounding areas. Many were members of local Amateur Dramatic companies and can be seen in scenes that are wildly different.

Included among the "1001 Movies You Must See Before You Die", edited by Steven Schneider.