In the aftermath of the nuclear blast, footage of a cat supposedly "suffocating" outside in the extreme heat is shown. This is actually footage of a cat enjoying a hefty dose of catnip, then they just reversed the film to give the impression of the cat suffocating (the way the cat is rolling on the ground is the giveaway).
While shooting the movie, the BBC got in trouble with local police when they detonated a large smoke bomb in order to simulate a nuclear explosion. Members of the public, who were not aware that a movie was being shot, panicked and thought that a real explosion had occurred.
Shortly after the film's broadcast on the BBC, Ronald Reagan made a speech that was less aggressive than expected. A cartoon on the front of the London Times on 25th September 1984 depicted one person reading a headline "Reagan's peace speech" and another asking, "Do you think he saw Threads?"
US television magnate Ted Turner wanted to air this film on TBS, his cable TV network, but couldn't find a sponsor. He decided to broadcast the film out of his own pocket.
In return for allowing Mick Jackson and Barry Hines to attend a training course for reconstruction after a nuclear attack, they agreed to show the film to Home Office officials in advance of broadcast. The officials criticised the film as exaggerated and likely to cause panic. As Jackson had done extensive research before the film, he was able to defend its content.