Created by Jack Morgan at the Cock N' Bull "British-style" pub on Sunset Strip, Hollywood, CA, USA, which was founded in 1937. The cocktail first appeared in Ted Saucier's Bottom's Up in 1951.
Half-fill a mixing jug with ice.
Add all ingredients and stir until well-chilled.
Strain into a chilled coupe over a cube of ice.
Garnish with an orange twist.