Wants to Use 1970s UK Public Service Films

Dear Rich: I was hoping to use sections of the script/narration from a series of UK Public information films from the 1970’s as one visual element in my original artwork. The lines are either a short sentence or part of a sentence (no more than 12 words in one piece or work), and the artwork will be sold in a very limited print run. We think you can use the material without seeking permission. Even if the copyright owner of this 40-year old source material saw your limited edition prints, it's unlikely they would bring an action as the copying is probably too trivial to cause any damage (de minimis copying). Alternatively, it might be excused as fair use because you're taking so little  (and you're transforming it).
Disclaimer Dept. We're writing about U.S. Copyright law. Britain doesn't have a fair use defense but it does have "fair dealing."
FYI Dept. We're pretty sure that's the remarkable Donald Pleasance narrating the first segment of our video.