Question: What does the term "grey dawn" mean?
Question: What does Admiral Nelson have in his left shirt pocket?
Answer: Admiral Nelson is puffing on cigars in a few scenes, and his cigars are even a source of dialogue in the film. Specifically, when his quarters catch on fire, the blaze is initially blamed on a lit cigar, to which Nelson angrily replies that he ran out of cigars before the fire ever occurred. So it's a pretty good bet that Nelson was carrying a cigar (or cigars) in his shirt pocket.
Answer: There's no specific meaning. Metaphorically, it would mean that it is the beginning of something that is dismal, is going to be long and difficult to achieve, or may not end well. Basically, it's a "bad omen."
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