What does Foggy’s “That man” mean?

[MelMyers]

He uses the phrase, even when he’s talking directly to someone. For example, he’ll say to Compo, hurry up, that man!
I‘ve never heard the phrase before.

 

[gothic]

It's a very "British Army" (old) saying.
Please correct me if I'm wrong (though be careful because nobody likes a clever clogs!)

 

[Barrychuckle]

Yes I agree with gothic, I'd have said it was an army term, probably said to also emphasise his perceived seniority of rank. Which was Foggy all over

 

[Eithne]

I agree, it's all about emphasizing seniority and rank. My guess is that officers would probably see such an endless procession of young men that it was pointless to learn all their names, and it may not have been encouraged to view them, or allow them to view themselves, as individuals rather than soldiers, so a generic term for addressing men would be needed.