I do wonder if Threads does exaggerate the effects, somewhat. Could the effects of such an event be so bad even basic English is no longer spoken?
I'm not sure about the English (and I'll abstain from making jokes about the state of it in today's UK
) but given the scenario things would probably be even worse than they're depicted in the movie. A nuclear exchange between East and West would have probably resulted in dramatic changes to the global climate including a dramatic drop in average temperatures
effectively killing of agriculture for years. Those are newer models, though. At the time the film was made, the effects and the longevity of nuclear winter were seen as less dramatic and pretty much the way they were depicted in the movie.