The Nat Gubbins is the long-forgotten Biltmore Hotel cocktail, created at the Cascades Bar.
“Nat Gubbins, the London columnist, came to write about what was going on and introduced a pre-luncheon drink at the Cascades Bar: half-port, half-brandy with a twist, no ice, served in a small wine glass. It was guaranteed to lull the senses and produce relaxation along with avoirdupois.”
“A pair of New York sports writers, Bill Corum and Quentin Reynolds, went back to their desks after a dip into the world of the Biltmore and, while reminiscing one evening at Twenty One, began to describe the drink to the bartender.”
“‘Yeah,’ the fellow said, ‘They call it a Nat Gubbins.'”
— Page 83, The Biltmore: Beacon For Miami by Helen Muir
After some research, I stumbled upon more information to support the above. The Nat Gubbins or simply a Port & Brandy is a common old school digestive remedy (verging on medicinal, depending on who you ask) in the United Kingdom.
Dive deep into the hotel’s history: