Belstaff iconic leather vintage Postal Messenger bag
Belstaff 554 Colonial Messenger Bag - Iconic Alternatives
I have no clue if this is an actual Belstaff bag but it was expensive and even if it isn't the classic one—or even a Belstaff—it's aesthetically pretty perfect. I can always
Belstaff Black Leather Messenger Bag | The Fedora Lounge
Belstaff Colonial Messenger Bag in Natural for Men | Lyst